diff --git a/.gitignore b/.gitignore
index c6d3bfd..4fae73f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -24,3 +24,4 @@ bin/
 src/
 slides/
 main
+node_modules
diff --git a/Makefile b/Makefile
index 6acc056..9fd568b 100644
--- a/Makefile
+++ b/Makefile
@@ -1,13 +1,14 @@
+GIT_SUMMARY := $(shell git describe --tags --dirty --always)
 REPO=msoedov/hacker-slides
 
 default: repo
 
 repo:
-	@echo $(REPO)
+	@echo $(REPO):$(GIT_SUMMARY) 
 
 build:
 	@GOOS=linux CGO_ENABLE=0 go build main.go
-	@docker build -t $(REPO) .
+	@docker build -t $(REPO):$(GIT_SUMMARY) .
 
 push:
-	@docker push $(REPO)
+	@docker push $(REPO):$(GIT_SUMMARY)
diff --git a/package.json b/package.json
index 0743e52..d59b141 100644
--- a/package.json
+++ b/package.json
@@ -1,5 +1,5 @@
 {
   "dependencies": {
-    "reveal.js": "^3.4.1"
+    "reveal.js": "^3.5.0"
   }
 }
diff --git a/static/reveal.js/Gruntfile.js b/static/reveal.js/Gruntfile.js
index 96a4f52..aa04b68 100644
--- a/static/reveal.js/Gruntfile.js
+++ b/static/reveal.js/Gruntfile.js
@@ -15,7 +15,7 @@ module.exports = function(grunt) {
 				' * http://lab.hakim.se/reveal-js\n' +
 				' * MIT licensed\n' +
 				' *\n' +
-				' * Copyright (C) 2016 Hakim El Hattab, http://hakim.se\n' +
+				' * Copyright (C) 2017 Hakim El Hattab, http://hakim.se\n' +
 				' */'
 		},
 
@@ -44,7 +44,7 @@ module.exports = function(grunt) {
 					{
 						expand: true,
 						cwd: 'css/theme/source',
-						src: ['*.scss'],
+						src: ['*.sass', '*.scss'],
 						dest: 'css/theme',
 						ext: '.css'
 					}
@@ -122,7 +122,12 @@ module.exports = function(grunt) {
 				tasks: 'js'
 			},
 			theme: {
-				files: [ 'css/theme/source/*.scss', 'css/theme/template/*.scss' ],
+				files: [
+					'css/theme/source/*.sass',
+					'css/theme/source/*.scss',
+					'css/theme/template/*.sass',
+					'css/theme/template/*.scss'
+				],
 				tasks: 'css-themes'
 			},
 			css: {
diff --git a/static/reveal.js/LICENSE b/static/reveal.js/LICENSE
index 924cd89..c3e6e5f 100644
--- a/static/reveal.js/LICENSE
+++ b/static/reveal.js/LICENSE
@@ -1,4 +1,4 @@
-Copyright (C) 2016 Hakim El Hattab, http://hakim.se, and reveal.js contributors
+Copyright (C) 2017 Hakim El Hattab, http://hakim.se, and reveal.js contributors
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
diff --git a/static/reveal.js/README.md b/static/reveal.js/README.md
index 8878842..7ec759a 100644
--- a/static/reveal.js/README.md
+++ b/static/reveal.js/README.md
@@ -105,17 +105,17 @@ The presentation markup hierarchy needs to be `.reveal > .slides > section` wher
 
 ### Markdown
 
-It's possible to write your slides using Markdown. To enable Markdown, add the `data-markdown` attribute to your `<section>` elements and wrap the contents in a `<script type="text/template">` like the example below.
+It's possible to write your slides using Markdown. To enable Markdown, add the `data-markdown` attribute to your `<section>` elements and wrap the contents in a `<textarea data-template>` like the example below.
 
 This is based on [data-markdown](https://gist.github.com/1343518) from [Paul Irish](https://github.com/paulirish) modified to use [marked](https://github.com/chjj/marked) to support [GitHub Flavored Markdown](https://help.github.com/articles/github-flavored-markdown). Sensitive to indentation (avoid mixing tabs and spaces) and line breaks (avoid consecutive breaks).
 
 ```html
 <section data-markdown>
-	<script type="text/template">
+	<textarea data-template>
 		## Page title
 
 		A paragraph with some text and a [link](http://hakim.se).
-	</script>
+	</textarea>
 </section>
 ```
 
@@ -187,6 +187,9 @@ Reveal.initialize({
 	// Display a presentation progress bar
 	progress: true,
 
+	// Set default timing of 2 minutes per slide
+	defaultTiming: 120,
+
 	// Display the page number of the current slide
 	slideNumber: false,
 
@@ -228,6 +231,12 @@ Reveal.initialize({
 	// Flags if speaker notes should be visible to all viewers
 	showNotes: false,
 
+	// Global override for autolaying embedded media (video/audio/iframe)
+	// - null: Media will only autoplay if data-autoplay is present
+	// - true: All media will autoplay, regardless of individual setting
+	// - false: No media will autoplay, regardless of individual setting
+	autoPlayMedia: null,
+
 	// Number of milliseconds between automatically proceeding to the
 	// next slide, disabled when set to 0, this value can be overwritten
 	// by using a data-autoslide attribute on your slides
@@ -270,7 +279,10 @@ Reveal.initialize({
 	// - Calculated automatically unless specified
 	// - Set to 0 to disable movement along an axis
 	parallaxBackgroundHorizontal: null,
-	parallaxBackgroundVertical: null
+	parallaxBackgroundVertical: null,
+
+	// The display mode that will be used to show slides
+	display: 'block'
 
 });
 ```
@@ -463,14 +475,15 @@ Reveal.nextFragment();
 // Randomize the order of slides
 Reveal.shuffle();
 
-// Shows a help overlay with keyboard shortcuts
-Reveal.showHelp();
-
 // Toggle presentation states, optionally pass true/false to force on/off
 Reveal.toggleOverview();
 Reveal.togglePause();
 Reveal.toggleAutoSlide();
 
+// Shows a help overlay with keyboard shortcuts, optionally pass true/false
+// to force on/off
+Reveal.toggleHelp();
+
 // Change a config value at runtime
 Reveal.configure({ controls: true });
 
@@ -484,9 +497,11 @@ Reveal.getScale();
 Reveal.getPreviousSlide();
 Reveal.getCurrentSlide();
 
-Reveal.getIndices(); // { h: 0, v: 0 } }
-Reveal.getProgress(); // 0-1
-Reveal.getTotalSlides();
+Reveal.getIndices();        // { h: 0, v: 0 } }
+Reveal.getPastSlideCount();
+Reveal.getProgress();       // (0 == first slide, 1 == last slide)
+Reveal.getSlides();         // Array of all slides
+Reveal.getTotalSlides();    // total number of slides
 
 // Returns the speaker notes for the current slide
 Reveal.getSlideNotes();
@@ -544,7 +559,7 @@ Reveal.addEventListener( 'somestate', function() {
 
 Slides are contained within a limited portion of the screen by default to allow them to fit any display and scale uniformly. You can apply full page backgrounds outside of the slide area by adding a ```data-background``` attribute to your ```<section>``` elements. Four different types of backgrounds are supported: color, image, video and iframe.
 
-##### Color Backgrounds
+#### Color Backgrounds
 All CSS color formats are supported, like rgba() or hsl().
 ```html
 <section data-background-color="#ff0000">
@@ -552,7 +567,7 @@ All CSS color formats are supported, like rgba() or hsl().
 </section>
 ```
 
-##### Image Backgrounds
+#### Image Backgrounds
 By default, background images are resized to cover the full page. Available options:
 
 | Attribute                    | Default    | Description |
@@ -570,7 +585,7 @@ By default, background images are resized to cover the full page. Available opti
 </section>
 ```
 
-##### Video Backgrounds
+#### Video Backgrounds
 Automatically plays a full size video behind the slide.
 
 | Attribute                    | Default | Description |
@@ -578,6 +593,7 @@ Automatically plays a full size video behind the slide.
 | data-background-video        |         | A single video source, or a comma separated list of video sources. |
 | data-background-video-loop   | false   | Flags if the video should play repeatedly. |
 | data-background-video-muted  | false   | Flags if the audio should be muted. |
+| data-background-size         | cover   | Use `cover` for full screen and some cropping or `contain` for letterboxing. |
 
 ```html
 <section data-background-video="https://s3.amazonaws.com/static.slid.es/site/homepage/v1/homepage-video-editor.mp4,https://s3.amazonaws.com/static.slid.es/site/homepage/v1/homepage-video-editor.webm" data-background-video-loop data-background-video-muted>
@@ -585,15 +601,15 @@ Automatically plays a full size video behind the slide.
 </section>
 ```
 
-##### Iframe Backgrounds
-Embeds a web page as a background. Note that since the iframe is in the background layer, behind your slides, it is not possible to interact with the embedded page.
+#### Iframe Backgrounds
+Embeds a web page as a slide background that covers 100% of the reveal.js width and height. The iframe is in the background layer, behind your slides, and as such it's not possible to interact with it by default. To make your background interactive, you can add the `data-background-interactive` attribute.
 ```html
-<section data-background-iframe="https://slides.com">
+<section data-background-iframe="https://slides.com" data-background-interactive>
 	<h2>Iframe</h2>
 </section>
 ```
 
-##### Background Transitions
+#### Background Transitions
 Backgrounds transition using a fade animation by default. This can be changed to a linear sliding transition by passing ```backgroundTransition: 'slide'``` to the ```Reveal.initialize()``` call. Alternatively you can set ```data-background-transition``` on any section with a background to override that specific transition.
 
 
@@ -749,7 +765,7 @@ By default, Reveal is configured with [highlight.js](https://highlightjs.org/) f
 ```
 
 ### Slide number
-If you would like to display the page number of the current slide you can do so using the ```slideNumber``` configuration value.
+If you would like to display the page number of the current slide you can do so using the ```slideNumber``` and ```showSlideNumber``` configuration values.
 
 ```javascript
 // Shows the slide number using default formatting
@@ -762,6 +778,12 @@ Reveal.configure({ slideNumber: true });
 //  "c/t": 	flattened slide number / total slides
 Reveal.configure({ slideNumber: 'c/t' });
 
+// Control which views the slide number displays on using the "showSlideNumber" value:
+//     "all": show on all views (default)
+// "speaker": only show slide numbers on speaker notes view
+//   "print": only show slide numbers when printing to PDF
+Reveal.configure({ showSlideNumber: 'speaker' });
+
 ```
 
 
@@ -778,20 +800,26 @@ Reveal.addEventListener( 'overviewhidden', function( event ) { /* ... */ } );
 Reveal.toggleOverview();
 ```
 
+
 ### Fullscreen mode
 Just press »F« on your keyboard to show your presentation in fullscreen mode. Press the »ESC« key to exit fullscreen mode.
 
 
 ### Embedded media
-Embedded HTML5 `<video>`/`<audio>` and YouTube iframes are automatically paused when you navigate away from a slide. This can be disabled by decorating your element with a `data-ignore` attribute.
-
 Add `data-autoplay` to your media element if you want it to automatically start playing when the slide is shown:
 
 ```html
 <video data-autoplay src="http://clips.vorwaerts-gmbh.de/big_buck_bunny.mp4"></video>
 ```
 
-Additionally the framework automatically pushes two [post messages](https://developer.mozilla.org/en-US/docs/Web/API/Window.postMessage) to all iframes, ```slide:start``` when the slide containing the iframe is made visible and ```slide:stop``` when it is hidden.
+If you want to enable or disable autoplay globally, for all embedded media, you can use the `autoPlayMedia` configuration option. If you set this to `true` ALL media will autoplay regardless of individual `data-autoplay` attributes. If you initialize with `autoPlayMedia: false` NO media will autoplay.
+
+Note that embedded HTML5 `<video>`/`<audio>` and YouTube/Vimeo iframes are automatically paused when you navigate away from a slide. This can be disabled by decorating your element with a `data-ignore` attribute.
+
+
+### Embedded iframes
+
+reveal.js automatically pushes two [post messages](https://developer.mozilla.org/en-US/docs/Web/API/Window.postMessage) to embedded iframes. ```slide:start``` when the slide containing the iframe is made visible and ```slide:stop``` when it is hidden.
 
 
 ### Stretching elements
@@ -847,15 +875,31 @@ Reveal.initialize({
 Presentations can be exported to PDF via a special print stylesheet. This feature requires that you use [Google Chrome](http://google.com/chrome) or [Chromium](https://www.chromium.org/Home) and to be serving the presention from a webserver.
 Here's an example of an exported presentation that's been uploaded to SlideShare: http://www.slideshare.net/hakimel/revealjs-300.
 
+### Page size
 Export dimensions are inferred from the configured [presentation size](#presentation-size). Slides that are too tall to fit within a single page will expand onto multiple pages. You can limit how many pages a slide may expand onto using the `pdfMaxPagesPerSlide` config option, for example `Reveal.configure({ pdfMaxPagesPerSlide: 1 })` ensures that no slide ever grows to more than one printed page.
 
-1. Open your presentation with `print-pdf` included in the query string i.e. http://localhost:8000/?print-pdf#/. This triggers the default index HTML to load the PDF print stylesheet ([css/print/pdf.css](https://github.com/hakimel/reveal.js/blob/master/css/print/pdf.css)). You can test this with [lab.hakim.se/reveal-js?print-pdf](http://lab.hakim.se/reveal-js?print-pdf).
-2. Open the in-browser print dialog (CTRL/CMD+P).
-3. Change the **Destination** setting to **Save as PDF**.
-4. Change the **Layout** to **Landscape**.
-5. Change the **Margins** to **None**.
-6. Enable the **Background graphics** option.
-7. Click **Save**.
+### Print stylesheet
+To enable the PDF print capability in your presentation, the special print stylesheet at [/css/print/pdf.css](https://github.com/hakimel/reveal.js/blob/master/css/print/pdf.css) must be loaded. The default index.html file handles this for you when `print-pdf` is included in the query string. If you're using a different HTML template, you can add this to your HEAD:
+
+```html
+<script>
+	var link = document.createElement( 'link' );
+	link.rel = 'stylesheet';
+	link.type = 'text/css';
+	link.href = window.location.search.match( /print-pdf/gi ) ? 'css/print/pdf.css' : 'css/print/paper.css';
+	document.getElementsByTagName( 'head' )[0].appendChild( link );
+</script>
+```
+
+### Instructions
+1. Open your presentation with `print-pdf` included in the query string i.e. http://localhost:8000/?print-pdf. You can test this with [lab.hakim.se/reveal-js?print-pdf](http://lab.hakim.se/reveal-js?print-pdf).
+  * If you want to include [speaker notes](#speaker-notes) in your export, you can append `showNotes=true` to the query string: http://localhost:8000/?print-pdf&showNotes=true
+1. Open the in-browser print dialog (CTRL/CMD+P).
+1. Change the **Destination** setting to **Save as PDF**.
+1. Change the **Layout** to **Landscape**.
+1. Change the **Margins** to **None**.
+1. Enable the **Background graphics** option.
+1. Click **Save**.
 
 ![Chrome Print Settings](https://s3.amazonaws.com/hakim-static/reveal-js/pdf-print-settings-2.png)
 
@@ -924,7 +968,18 @@ This will only display in the notes window.
 
 Notes are only visible to the speaker inside of the speaker view. If you wish to share your notes with others you can initialize reveal.js with the `showNotes` config value set to `true`. Notes will appear along the bottom of the presentations.
 
-When `showNotes` is enabled notes are also included when you [export to PDF](https://github.com/hakimel/reveal.js#pdf-export). By default, notes are printed in a semi-transparent box on top of slide. If you'd rather print them on a separate page after the slide, set `showNotes: "separate-page"`.
+When `showNotes` is enabled notes are also included when you [export to PDF](https://github.com/hakimel/reveal.js#pdf-export). By default, notes are printed in a semi-transparent box on top of the slide. If you'd rather print them on a separate page after the slide, set `showNotes: "separate-page"`.
+
+#### Speaker notes clock and timers
+
+The speaker notes window will also show:
+
+- Time elapsed since the beginning of the presentation.  If you hover the mouse above this section, a timer reset button will appear.
+- Current wall-clock time
+- (Optionally) a pacing timer which indicates whether the current pace of the presentation is on track for the right timing (shown in green), and if not, whether the presenter should speed up (shown in red) or has the luxury of slowing down (blue).
+
+The pacing timer can be enabled by configuring by the `defaultTiming` parameter in the `Reveal` configuration block, which specifies the number of seconds per slide.  120 can be a reasonable rule of thumb.  Timings can also be given per slide `<section>` by setting the `data-timing` attribute.  Both values are in numbers of seconds.
+
 
 ## Server Side Speaker Notes
 
@@ -1026,11 +1081,13 @@ Server that receives the slideChanged events from the master presentation and br
 1. ```npm install```
 2. ```node plugin/multiplex```
 
-Or you use the socket.io server at [https://reveal-js-multiplex-ccjbegmaii.now.sh/](https://reveal-js-multiplex-ccjbegmaii.now.sh/).
+Or you can use the socket.io server at [https://reveal-js-multiplex-ccjbegmaii.now.sh/](https://reveal-js-multiplex-ccjbegmaii.now.sh/).
 
 You'll need to generate a unique secret and token pair for your master and client presentations. To do so, visit ```http://example.com/token```, where ```http://example.com``` is the location of your socket.io server. Or if you're going to use the socket.io server at [https://reveal-js-multiplex-ccjbegmaii.now.sh/](https://reveal-js-multiplex-ccjbegmaii.now.sh/), visit [https://reveal-js-multiplex-ccjbegmaii.now.sh/token](https://reveal-js-multiplex-ccjbegmaii.now.sh/token).
 
-You are very welcome to point your presentations at the Socket.io server running at [https://reveal-js-multiplex-ccjbegmaii.now.sh/](https://reveal-js-multiplex-ccjbegmaii.now.sh/), but availability and stability are not guaranteed. For anything mission critical I recommend you run your own server. It is simple to deploy to nodejitsu, heroku, your own environment, etc.
+You are very welcome to point your presentations at the Socket.io server running at [https://reveal-js-multiplex-ccjbegmaii.now.sh/](https://reveal-js-multiplex-ccjbegmaii.now.sh/), but availability and stability are not guaranteed.
+
+For anything mission critical I recommend you run your own server. The easiest way to do this is by installing [now](https://zeit.co/now). With that installed, deploying your own Multiplex server is as easy running the following command from the reveal.js folder: `now plugin/multiplex`.
 
 ##### socket.io server as file static server
 
@@ -1096,7 +1153,7 @@ Reveal.initialize({
 	// other options ...
 
 	math: {
-		mathjax: 'https://cdn.mathjax.org/mathjax/latest/MathJax.js',
+		mathjax: 'https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.0/MathJax.js',
 		config: 'TeX-AMS_HTML-full'  // See http://docs.mathjax.org/en/latest/config-files.html
 	},
 
@@ -1153,7 +1210,7 @@ Some reveal.js features, like external Markdown and speaker notes, require that
 
 1. Open <http://localhost:8000> to view your presentation
 
-   You can change the port by using `npm start -- --port 8001`.
+   You can change the port by using `npm start -- --port=8001`.
 
 
 ### Folder Structure
@@ -1167,4 +1224,4 @@ Some reveal.js features, like external Markdown and speaker notes, require that
 
 MIT licensed
 
-Copyright (C) 2016 Hakim El Hattab, http://hakim.se
+Copyright (C) 2017 Hakim El Hattab, http://hakim.se
diff --git a/static/reveal.js/bower.json b/static/reveal.js/bower.json
index c7c312d..ff18de4 100644
--- a/static/reveal.js/bower.json
+++ b/static/reveal.js/bower.json
@@ -1,6 +1,6 @@
 {
   "name": "reveal.js",
-  "version": "3.4.1",
+  "version": "3.5.0",
   "main": [
     "js/reveal.js",
     "css/reveal.css"
diff --git a/static/reveal.js/css/print/pdf.css b/static/reveal.js/css/print/pdf.css
index 8c3234c..20c646a 100644
--- a/static/reveal.js/css/print/pdf.css
+++ b/static/reveal.js/css/print/pdf.css
@@ -87,14 +87,14 @@ ul, ol, div, p {
 	position: relative;
 	overflow: hidden;
 	z-index: 1;
+
+	page-break-after: always;
 }
 
 .reveal .slides section {
-	page-break-after: always !important;
-
 	visibility: visible !important;
 	display: block !important;
-	position: relative !important;
+	position: absolute !important;
 
 	margin: 0 !important;
 	padding: 0 !important;
@@ -115,6 +115,7 @@ ul, ol, div, p {
 }
 
 .reveal section.stack {
+	position: relative !important;
 	margin: 0 !important;
 	padding: 0 !important;
 	page-break-after: avoid !important;
diff --git a/static/reveal.js/css/reveal.css b/static/reveal.js/css/reveal.css
index 430dcde..5f501b1 100644
--- a/static/reveal.js/css/reveal.css
+++ b/static/reveal.js/css/reveal.css
@@ -3,7 +3,7 @@
  * http://lab.hakim.se/reveal-js
  * MIT licensed
  *
- * Copyright (C) 2016 Hakim El Hattab, http://hakim.se
+ * Copyright (C) 2017 Hakim El Hattab, http://hakim.se
  */
 /*********************************************
  * RESET STYLES
@@ -323,6 +323,7 @@ body {
   bottom: 0;
   left: 0;
   margin: auto;
+  pointer-events: none;
   overflow: visible;
   z-index: 1;
   text-align: center;
@@ -340,6 +341,7 @@ body {
   position: absolute;
   width: 100%;
   padding: 20px 0px;
+  pointer-events: auto;
   z-index: 10;
   -webkit-transform-style: flat;
           transform-style: flat;
@@ -374,6 +376,12 @@ body {
   z-index: 11;
   opacity: 1; }
 
+.reveal .slides > section:empty,
+.reveal .slides > section > section:empty,
+.reveal .slides > section[data-background-interactive],
+.reveal .slides > section > section[data-background-interactive] {
+  pointer-events: none; }
+
 .reveal.center,
 .reveal.center .slides,
 .reveal.center .slides section {
@@ -589,6 +597,10 @@ body {
 
 /*********************************************
  * CUBE TRANSITION
+ *
+ * WARNING:
+ * this is deprecated and will be removed in a
+ * future version.
  *********************************************/
 .reveal.cube .slides {
   -webkit-perspective: 1300px;
@@ -664,6 +676,10 @@ body {
 
 /*********************************************
  * PAGE TRANSITION
+ *
+ * WARNING:
+ * this is deprecated and will be removed in a
+ * future version.
  *********************************************/
 .reveal.page .slides {
   -webkit-perspective-origin: 0% 50%;
@@ -839,6 +855,7 @@ body {
   height: 100%;
   opacity: 0;
   visibility: hidden;
+  overflow: hidden;
   background-color: transparent;
   background-position: 50% 50%;
   background-repeat: no-repeat;
@@ -851,7 +868,8 @@ body {
 
 .reveal .slide-background.present {
   opacity: 1;
-  visibility: visible; }
+  visibility: visible;
+  z-index: 2; }
 
 .print-pdf .reveal .slide-background {
   opacity: 1 !important;
@@ -865,7 +883,13 @@ body {
   max-width: none;
   max-height: none;
   top: 0;
-  left: 0; }
+  left: 0;
+  -o-object-fit: cover;
+     object-fit: cover; }
+
+.reveal .slide-background[data-background-size="contain"] video {
+  -o-object-fit: contain;
+     object-fit: contain; }
 
 /* Immediate transition style */
 .reveal[data-background-transition=none] > .backgrounds .slide-background,
@@ -1037,6 +1061,8 @@ body {
     visibility: visible;
     outline: 10px solid rgba(150, 150, 150, 0.1);
     outline-offset: 10px; }
+  .reveal.overview .backgrounds .slide-background.stack {
+    overflow: visible; }
 
 .reveal.overview .slides section,
 .reveal.overview-deactivating .slides section {
@@ -1048,10 +1074,6 @@ body {
   -webkit-transition: none;
           transition: none; }
 
-.reveal.overview-animated .slides {
-  -webkit-transition: -webkit-transform 0.4s ease;
-          transition: transform 0.4s ease; }
-
 /*********************************************
  * RTL SUPPORT
  *********************************************/
diff --git a/static/reveal.js/css/reveal.scss b/static/reveal.js/css/reveal.scss
index 22fb3fe..983e587 100644
--- a/static/reveal.js/css/reveal.scss
+++ b/static/reveal.js/css/reveal.scss
@@ -3,7 +3,7 @@
  * http://lab.hakim.se/reveal-js
  * MIT licensed
  *
- * Copyright (C) 2016 Hakim El Hattab, http://hakim.se
+ * Copyright (C) 2017 Hakim El Hattab, http://hakim.se
  */
 
 
@@ -388,6 +388,7 @@ body {
 	bottom: 0;
 	left: 0;
 	margin: auto;
+	pointer-events: none;
 
 	overflow: visible;
 	z-index: 1;
@@ -406,6 +407,7 @@ body {
 	position: absolute;
 	width: 100%;
 	padding: 20px 0px;
+	pointer-events: auto;
 
 	z-index: 10;
 	transform-style: flat;
@@ -443,6 +445,13 @@ body {
 	opacity: 1;
 }
 
+.reveal .slides>section:empty,
+.reveal .slides>section>section:empty,
+.reveal .slides>section[data-background-interactive],
+.reveal .slides>section>section[data-background-interactive] {
+	pointer-events: none;
+}
+
 .reveal.center,
 .reveal.center .slides,
 .reveal.center .slides section {
@@ -610,6 +619,10 @@ body {
 
 /*********************************************
  * CUBE TRANSITION
+ *
+ * WARNING:
+ * this is deprecated and will be removed in a
+ * future version.
  *********************************************/
 
 .reveal.cube .slides {
@@ -682,6 +695,10 @@ body {
 
 /*********************************************
  * PAGE TRANSITION
+ *
+ * WARNING:
+ * this is deprecated and will be removed in a
+ * future version.
  *********************************************/
 
 .reveal.page .slides {
@@ -866,6 +883,7 @@ body {
 		height: 100%;
 		opacity: 0;
 		visibility: hidden;
+		overflow: hidden;
 
 		background-color: rgba( 0, 0, 0, 0 );
 		background-position: 50% 50%;
@@ -882,6 +900,7 @@ body {
 	.reveal .slide-background.present {
 		opacity: 1;
 		visibility: visible;
+		z-index: 2;
 	}
 
 	.print-pdf .reveal .slide-background {
@@ -898,7 +917,11 @@ body {
 	max-height: none;
 	top: 0;
 	left: 0;
+	object-fit: cover;
 }
+	.reveal .slide-background[data-background-size="contain"] video {
+		object-fit: contain;
+	}
 
 /* Immediate transition style */
 .reveal[data-background-transition=none]>.backgrounds .slide-background,
@@ -1080,6 +1103,10 @@ body {
 		outline: 10px solid rgba(150,150,150,0.1);
 		outline-offset: 10px;
 	}
+
+	.backgrounds .slide-background.stack {
+		overflow: visible;
+	}
 }
 
 // Disable transitions transitions while we're activating
@@ -1094,10 +1121,6 @@ body {
 	transition: none;
 }
 
-.reveal.overview-animated .slides {
-	transition: transform 0.4s ease;
-}
-
 
 /*********************************************
  * RTL SUPPORT
diff --git a/static/reveal.js/index.html b/static/reveal.js/index.html
index 0c7a672..98accc3 100644
--- a/static/reveal.js/index.html
+++ b/static/reveal.js/index.html
@@ -33,11 +33,10 @@
 		<script src="js/reveal.js"></script>
 
 		<script>
-			// More info https://github.com/hakimel/reveal.js#configuration
+			// More info about config & dependencies:
+			// - https://github.com/hakimel/reveal.js#configuration
+			// - https://github.com/hakimel/reveal.js#dependencies
 			Reveal.initialize({
-				history: true,
-
-				// More info https://github.com/hakimel/reveal.js#dependencies
 				dependencies: [
 					{ src: 'plugin/markdown/marked.js' },
 					{ src: 'plugin/markdown/markdown.js' },
diff --git a/static/reveal.js/js/reveal.js b/static/reveal.js/js/reveal.js
index 9251dc0..d3ba03c 100644
--- a/static/reveal.js/js/reveal.js
+++ b/static/reveal.js/js/reveal.js
@@ -3,7 +3,7 @@
  * http://lab.hakim.se/reveal-js
  * MIT licensed
  *
- * Copyright (C) 2016 Hakim El Hattab, http://hakim.se
+ * Copyright (C) 2017 Hakim El Hattab, http://hakim.se
  */
 (function( root, factory ) {
 	if( typeof define === 'function' && define.amd ) {
@@ -26,7 +26,7 @@
 	var Reveal;
 
 	// The reveal.js version
-	var VERSION = '3.4.1';
+	var VERSION = '3.5.0';
 
 	var SLIDES_SELECTOR = '.slides section',
 		HORIZONTAL_SLIDES_SELECTOR = '.slides>section',
@@ -58,6 +58,9 @@
 			// Display the page number of the current slide
 			slideNumber: false,
 
+			// Determine which displays to show the slide number on
+			showSlideNumber: 'all',
+
 			// Push each slide change to the browser history
 			history: false,
 
@@ -102,6 +105,12 @@
 			// Flags if speaker notes should be visible to all viewers
 			showNotes: false,
 
+			// Global override for autolaying embedded media (video/audio/iframe)
+			// - null: Media will only autoplay if data-autoplay is present
+			// - true: All media will autoplay, regardless of individual setting
+			// - false: No media will autoplay, regardless of individual setting
+			autoPlayMedia: null,
+
 			// Number of milliseconds between automatically proceeding to the
 			// next slide, disabled when set to 0, this value can be overwritten
 			// by using a data-autoslide attribute on your slides
@@ -157,9 +166,19 @@
 			// to PDF, unlimited by default
 			pdfMaxPagesPerSlide: Number.POSITIVE_INFINITY,
 
+			// Offset used to reduce the height of content within exported PDF pages.
+			// This exists to account for environment differences based on how you
+			// print to PDF. CLI printing options, like phantomjs and wkpdf, can end
+			// on precisely the total height of the document whereas in-browser
+			// printing has to end one pixel before.
+			pdfPageHeightOffset: -1,
+
 			// Number of slides away from the current that are visible
 			viewDistance: 3,
 
+			// The display mode that will be used to show slides
+			display: 'block',
+
 			// Script dependencies to load
 			dependencies: []
 
@@ -605,7 +624,7 @@
 			slideHeight = slideSize.height;
 
 		// Let the browser know what page size we want to print
-		injectStyleSheet( '@page{size:'+ pageWidth +'px '+ pageHeight +'px; margin: 0 0 -1px 0;}' );
+		injectStyleSheet( '@page{size:'+ pageWidth +'px '+ pageHeight +'px; margin: 0px;}' );
 
 		// Limit the size of certain elements to the dimensions of the slide
 		injectStyleSheet( '.reveal section>img, .reveal section>video, .reveal section>iframe{max-width: '+ slideWidth +'px; max-height:'+ slideHeight +'px}' );
@@ -614,6 +633,9 @@
 		document.body.style.width = pageWidth + 'px';
 		document.body.style.height = pageHeight + 'px';
 
+		// Make sure stretch elements fit on slide
+		layoutSlideContents( slideWidth, slideHeight );
+
 		// Add each slide's index as attributes on itself, we need these
 		// indices to generate slide numbers below
 		toArray( dom.wrapper.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR ) ).forEach( function( hslide, h ) {
@@ -652,7 +674,7 @@
 				// so that no page ever flows onto another
 				var page = document.createElement( 'div' );
 				page.className = 'pdf-page';
-				page.style.height = ( pageHeight * numberOfPages ) + 'px';
+				page.style.height = ( ( pageHeight + config.pdfPageHeightOffset ) * numberOfPages ) + 'px';
 				slide.parentNode.insertBefore( page, slide );
 				page.appendChild( slide );
 
@@ -695,7 +717,7 @@
 				}
 
 				// Inject slide numbers if `slideNumbers` are enabled
-				if( config.slideNumber ) {
+				if( config.slideNumber && /all|print/i.test( config.showSlideNumber ) ) {
 					var slideNumberH = parseInt( slide.getAttribute( 'data-index-h' ), 10 ) + 1,
 						slideNumberV = parseInt( slide.getAttribute( 'data-index-v' ), 10 ) + 1;
 
@@ -859,7 +881,7 @@
 
 		if( data.background ) {
 			// Auto-wrap image urls in url(...)
-			if( /^(http|file|\/\/)/gi.test( data.background ) || /\.(svg|png|jpg|jpeg|gif|bmp)$/gi.test( data.background ) ) {
+			if( /^(http|file|\/\/)/gi.test( data.background ) || /\.(svg|png|jpg|jpeg|gif|bmp)([?#]|$)/gi.test( data.background ) ) {
 				slide.setAttribute( 'data-background-image', data.background );
 			}
 			else {
@@ -884,6 +906,7 @@
 
 		// Additional and optional background properties
 		if( data.backgroundSize ) element.style.backgroundSize = data.backgroundSize;
+		if( data.backgroundSize ) element.setAttribute( 'data-background-size', data.backgroundSize );
 		if( data.backgroundColor ) element.style.backgroundColor = data.backgroundColor;
 		if( data.backgroundRepeat ) element.style.backgroundRepeat = data.backgroundRepeat;
 		if( data.backgroundPosition ) element.style.backgroundPosition = data.backgroundPosition;
@@ -977,7 +1000,6 @@
 
 		dom.controls.style.display = config.controls ? 'block' : 'none';
 		dom.progress.style.display = config.progress ? 'block' : 'none';
-		dom.slideNumber.style.display = config.slideNumber && !isPrintingPDF() ? 'block' : 'none';
 
 		if( config.shuffle ) {
 			shuffle();
@@ -1030,10 +1052,11 @@
 		// Iframe link previews
 		if( config.previewLinks ) {
 			enablePreviewLinks();
+			disablePreviewLinks( '[data-preview-link=false]' );
 		}
 		else {
 			disablePreviewLinks();
-			enablePreviewLinks( '[data-preview-link]' );
+			enablePreviewLinks( '[data-preview-link]:not([data-preview-link=false])' );
 		}
 
 		// Remove existing auto-slide controls
@@ -1060,6 +1083,19 @@
 			} );
 		}
 
+		// Slide numbers
+		var slideNumberDisplay = 'none';
+		if( config.slideNumber && !isPrintingPDF() ) {
+			if( config.showSlideNumber === 'all' ) {
+				slideNumberDisplay = 'block';
+			}
+			else if( config.showSlideNumber === 'speaker' && isSpeakerNotes() ) {
+				slideNumberDisplay = 'block';
+			}
+		}
+
+		dom.slideNumber.style.display = slideNumberDisplay;
+
 		sync();
 
 	}
@@ -1225,7 +1261,7 @@
 			if( value === 'null' ) return null;
 			else if( value === 'true' ) return true;
 			else if( value === 'false' ) return false;
-			else if( value.match( /^\d+$/ ) ) return parseFloat( value );
+			else if( value.match( /^[\d\.]+$/ ) ) return parseFloat( value );
 		}
 
 		return value;
@@ -1426,7 +1462,7 @@
 	 * target element.
 	 *
 	 * remaining height = [ configured parent height ] - [ current parent height ]
-	 * 
+	 *
 	 * @param {HTMLElement} element
 	 * @param {number} [height]
 	 */
@@ -1569,9 +1605,9 @@
 	/**
 	 * Unbind preview frame links.
 	 */
-	function disablePreviewLinks() {
+	function disablePreviewLinks( selector ) {
 
-		var anchors = toArray( document.querySelectorAll( 'a' ) );
+		var anchors = toArray( document.querySelectorAll( selector ? selector : 'a' ) );
 
 		anchors.forEach( function( element ) {
 			if( /^(http|www)/gi.test( element.getAttribute( 'href' ) ) ) {
@@ -1628,6 +1664,28 @@
 
 	}
 
+	/**
+	 * Open or close help overlay window.
+	 *
+	 * @param {Boolean} [override] Flag which overrides the
+	 * toggle logic and forcibly sets the desired state. True means
+	 * help is open, false means it's closed.
+	 */
+	function toggleHelp( override ){
+
+		if( typeof override === 'boolean' ) {
+			override ? showHelp() : closeOverlay();
+		}
+		else {
+			if( dom.overlay ) {
+				closeOverlay();
+			}
+			else {
+				showHelp();
+			}
+		}
+	}
+
 	/**
 	 * Opens an overlay window with help material.
 	 */
@@ -1770,6 +1828,10 @@
 			updateProgress();
 			updateParallax();
 
+			if( isOverview() ) {
+				updateOverview();
+			}
+
 		}
 
 	}
@@ -1985,11 +2047,14 @@
 	 */
 	function updateOverview() {
 
+		var vmin = Math.min( window.innerWidth, window.innerHeight );
+		var scale = Math.max( vmin / 5, 150 ) / vmin;
+
 		transformSlides( {
 			overview: [
+				'scale('+ scale +')',
 				'translateX('+ ( -indexh * overviewSlideWidth ) +'px)',
-				'translateY('+ ( -indexv * overviewSlideHeight ) +'px)',
-				'translateZ('+ ( window.innerWidth < 400 ? -1000 : -2500 ) +'px)'
+				'translateY('+ ( -indexv * overviewSlideHeight ) +'px)'
 			].join( ' ' )
 		} );
 
@@ -2395,13 +2460,20 @@
 
 		updateControls();
 		updateProgress();
-		updateBackground( true );
 		updateSlideNumber();
 		updateSlidesVisibility();
+		updateBackground( true );
 		updateNotes();
 
 		formatEmbeddedContent();
-		startEmbeddedContent( currentSlide );
+
+		// Start or stop embedded content depending on global config
+		if( config.autoPlayMedia === false ) {
+			stopEmbeddedContent( currentSlide );
+		}
+		else {
+			startEmbeddedContent( currentSlide );
+		}
 
 		if( isOverview() ) {
 			layoutOverview();
@@ -2873,34 +2945,17 @@
 
 		} );
 
-		// Stop any currently playing video background
+		// Stop content inside of previous backgrounds
 		if( previousBackground ) {
 
-			var previousVideo = previousBackground.querySelector( 'video' );
-			if( previousVideo ) previousVideo.pause();
+			stopEmbeddedContent( previousBackground );
 
 		}
 
+		// Start content in the current background
 		if( currentBackground ) {
 
-			// Start video playback
-			var currentVideo = currentBackground.querySelector( 'video' );
-			if( currentVideo ) {
-
-				var startVideo = function() {
-					currentVideo.currentTime = 0;
-					currentVideo.play();
-					currentVideo.removeEventListener( 'loadeddata', startVideo );
-				};
-
-				if( currentVideo.readyState > 1 ) {
-					startVideo();
-				}
-				else {
-					currentVideo.addEventListener( 'loadeddata', startVideo );
-				}
-
-			}
+			startEmbeddedContent( currentBackground );
 
 			var backgroundImageURL = currentBackground.style.backgroundImage || '';
 
@@ -2999,6 +3054,13 @@
 
 	}
 
+	/**
+	 * Called when the given slide is within the configured view
+	 * distance. Shows the slide element and loads any content
+	 * that is set to load lazily (data-src).
+	 *
+	 * @param {HTMLElement} slide Slide to show
+	 */
 	/**
 	 * Called when the given slide is within the configured view
 	 * distance. Shows the slide element and loads any content
@@ -3009,7 +3071,7 @@
 	function showSlide( slide ) {
 
 		// Show the slide element
-		slide.style.display = 'block';
+		slide.style.display = config.display;
 
 		// Media elements with data-src attributes
 		toArray( slide.querySelectorAll( 'img[data-src], video[data-src], audio[data-src]' ) ).forEach( function( element ) {
@@ -3067,6 +3129,15 @@
 						video.muted = true;
 					}
 
+					// Inline video playback works (at least in Mobile Safari) as
+					// long as the video is muted and the `playsinline` attribute is
+					// present
+					if( isMobileDevice ) {
+						video.muted = true;
+						video.autoplay = true;
+						video.setAttribute( 'playsinline', '' );
+					}
+
 					// Support comma separated lists of video sources
 					backgroundVideo.split( ',' ).forEach( function( source ) {
 						video.innerHTML += '<source src="'+ source +'">';
@@ -3077,15 +3148,28 @@
 				// Iframes
 				else if( backgroundIframe ) {
 					var iframe = document.createElement( 'iframe' );
+					iframe.setAttribute( 'allowfullscreen', '' );
+					iframe.setAttribute( 'mozallowfullscreen', '' );
+					iframe.setAttribute( 'webkitallowfullscreen', '' );
+
+					// Only load autoplaying content when the slide is shown to
+					// avoid having it play in the background
+					if( /autoplay=(1|true|yes)/gi.test( backgroundIframe ) ) {
+						iframe.setAttribute( 'data-src', backgroundIframe );
+					}
+					else {
 						iframe.setAttribute( 'src', backgroundIframe );
-						iframe.style.width  = '100%';
-						iframe.style.height = '100%';
-						iframe.style.maxHeight = '100%';
-						iframe.style.maxWidth = '100%';
+					}
+
+					iframe.style.width  = '100%';
+					iframe.style.height = '100%';
+					iframe.style.maxHeight = '100%';
+					iframe.style.maxWidth = '100%';
 
 					background.appendChild( iframe );
 				}
 			}
+
 		}
 
 	}
@@ -3189,11 +3273,12 @@
 	 * Start playback of any embedded content inside of
 	 * the given element.
 	 *
-	 * @param {HTMLElement} slide
+	 * @param {HTMLElement} element
 	 */
 	function startEmbeddedContent( element ) {
 
 		if( element && !isSpeakerNotes() ) {
+
 			// Restart GIFs
 			toArray( element.querySelectorAll( 'img[src$=".gif"]' ) ).forEach( function( el ) {
 				// Setting the same unchanged source like this was confirmed
@@ -3207,8 +3292,25 @@
 					return;
 				}
 
-				if( el.hasAttribute( 'data-autoplay' ) && typeof el.play === 'function' ) {
-					el.play();
+				// Prefer an explicit global autoplay setting
+				var autoplay = config.autoPlayMedia;
+
+				// If no global setting is available, fall back on the element's
+				// own autoplay setting
+				if( typeof autoplay !== 'boolean' ) {
+					autoplay = el.hasAttribute( 'data-autoplay' ) || !!closestParent( el, '.slide-background' );
+				}
+
+				if( autoplay && typeof el.play === 'function' ) {
+
+					if( el.readyState > 1 ) {
+						startEmbeddedMedia( { target: el } );
+					}
+					else {
+						el.removeEventListener( 'loadeddata', startEmbeddedMedia ); // remove first to avoid dupes
+						el.addEventListener( 'loadeddata', startEmbeddedMedia );
+					}
+
 				}
 			} );
 
@@ -3233,15 +3335,36 @@
 					el.setAttribute( 'src', el.getAttribute( 'data-src' ) );
 				}
 			} );
+
 		}
 
 	}
 
+	/**
+	 * Starts playing an embedded video/audio element after
+	 * it has finished loading.
+	 *
+	 * @param {object} event
+	 */
+	function startEmbeddedMedia( event ) {
+
+		var isAttachedToDOM = !!closestParent( event.target, 'html' ),
+			isVisible  		= !!closestParent( event.target, '.present' );
+
+		if( isAttachedToDOM && isVisible ) {
+			event.target.currentTime = 0;
+			event.target.play();
+		}
+
+		event.target.removeEventListener( 'loadeddata', startEmbeddedMedia );
+
+	}
+
 	/**
 	 * "Starts" the content of an embedded iframe using the
 	 * postMessage API.
 	 *
-	 * @param {object} event - postMessage API event
+	 * @param {object} event
 	 */
 	function startEmbeddedIframe( event ) {
 
@@ -3249,17 +3372,33 @@
 
 		if( iframe && iframe.contentWindow ) {
 
-			// YouTube postMessage API
-			if( /youtube\.com\/embed\//.test( iframe.getAttribute( 'src' ) ) && iframe.hasAttribute( 'data-autoplay' ) ) {
-				iframe.contentWindow.postMessage( '{"event":"command","func":"playVideo","args":""}', '*' );
-			}
-			// Vimeo postMessage API
-			else if( /player\.vimeo\.com\//.test( iframe.getAttribute( 'src' ) ) && iframe.hasAttribute( 'data-autoplay' ) ) {
-				iframe.contentWindow.postMessage( '{"method":"play"}', '*' );
-			}
-			// Generic postMessage API
-			else {
-				iframe.contentWindow.postMessage( 'slide:start', '*' );
+			var isAttachedToDOM = !!closestParent( event.target, 'html' ),
+				isVisible  		= !!closestParent( event.target, '.present' );
+
+			if( isAttachedToDOM && isVisible ) {
+
+				// Prefer an explicit global autoplay setting
+				var autoplay = config.autoPlayMedia;
+
+				// If no global setting is available, fall back on the element's
+				// own autoplay setting
+				if( typeof autoplay !== 'boolean' ) {
+					autoplay = iframe.hasAttribute( 'data-autoplay' ) || !!closestParent( iframe, '.slide-background' );
+				}
+
+				// YouTube postMessage API
+				if( /youtube\.com\/embed\//.test( iframe.getAttribute( 'src' ) ) && autoplay ) {
+					iframe.contentWindow.postMessage( '{"event":"command","func":"playVideo","args":""}', '*' );
+				}
+				// Vimeo postMessage API
+				else if( /player\.vimeo\.com\//.test( iframe.getAttribute( 'src' ) ) && autoplay ) {
+					iframe.contentWindow.postMessage( '{"method":"play"}', '*' );
+				}
+				// Generic postMessage API
+				else {
+					iframe.contentWindow.postMessage( 'slide:start', '*' );
+				}
+
 			}
 
 		}
@@ -3270,40 +3409,41 @@
 	 * Stop playback of any embedded content inside of
 	 * the targeted slide.
 	 *
-	 * @param {HTMLElement} slide
+	 * @param {HTMLElement} element
 	 */
-	function stopEmbeddedContent( slide ) {
+	function stopEmbeddedContent( element ) {
 
-		if( slide && slide.parentNode ) {
+		if( element && element.parentNode ) {
 			// HTML5 media elements
-			toArray( slide.querySelectorAll( 'video, audio' ) ).forEach( function( el ) {
+			toArray( element.querySelectorAll( 'video, audio' ) ).forEach( function( el ) {
 				if( !el.hasAttribute( 'data-ignore' ) && typeof el.pause === 'function' ) {
+					el.setAttribute('data-paused-by-reveal', '');
 					el.pause();
 				}
 			} );
 
 			// Generic postMessage API for non-lazy loaded iframes
-			toArray( slide.querySelectorAll( 'iframe' ) ).forEach( function( el ) {
-				el.contentWindow.postMessage( 'slide:stop', '*' );
+			toArray( element.querySelectorAll( 'iframe' ) ).forEach( function( el ) {
+				if( el.contentWindow ) el.contentWindow.postMessage( 'slide:stop', '*' );
 				el.removeEventListener( 'load', startEmbeddedIframe );
 			});
 
 			// YouTube postMessage API
-			toArray( slide.querySelectorAll( 'iframe[src*="youtube.com/embed/"]' ) ).forEach( function( el ) {
-				if( !el.hasAttribute( 'data-ignore' ) && typeof el.contentWindow.postMessage === 'function' ) {
+			toArray( element.querySelectorAll( 'iframe[src*="youtube.com/embed/"]' ) ).forEach( function( el ) {
+				if( !el.hasAttribute( 'data-ignore' ) && el.contentWindow && typeof el.contentWindow.postMessage === 'function' ) {
 					el.contentWindow.postMessage( '{"event":"command","func":"pauseVideo","args":""}', '*' );
 				}
 			});
 
 			// Vimeo postMessage API
-			toArray( slide.querySelectorAll( 'iframe[src*="player.vimeo.com/"]' ) ).forEach( function( el ) {
-				if( !el.hasAttribute( 'data-ignore' ) && typeof el.contentWindow.postMessage === 'function' ) {
+			toArray( element.querySelectorAll( 'iframe[src*="player.vimeo.com/"]' ) ).forEach( function( el ) {
+				if( !el.hasAttribute( 'data-ignore' ) && el.contentWindow && typeof el.contentWindow.postMessage === 'function' ) {
 					el.contentWindow.postMessage( '{"method":"pause"}', '*' );
 				}
 			});
 
 			// Lazy loading iframes
-			toArray( slide.querySelectorAll( 'iframe[data-src]' ) ).forEach( function( el ) {
+			toArray( element.querySelectorAll( 'iframe[data-src]' ) ).forEach( function( el ) {
 				// Only removing the src doesn't actually unload the frame
 				// in all browsers (Firefox) so we set it to blank first
 				el.setAttribute( 'src', 'about:blank' );
@@ -3546,6 +3686,15 @@
 
 	}
 
+	/**
+	 * Retrieves all slides in this presentation.
+	 */
+	function getSlides() {
+
+		return toArray( dom.wrapper.querySelectorAll( SLIDES_SELECTOR + ':not(.stack)' ));
+
+	}
+
 	/**
 	 * Retrieves the total number of slides in this presentation.
 	 *
@@ -3553,7 +3702,7 @@
 	 */
 	function getTotalSlides() {
 
-		return dom.wrapper.querySelectorAll( SLIDES_SELECTOR + ':not(.stack)' ).length;
+		return getSlides().length;
 
 	}
 
@@ -3900,7 +4049,7 @@
 			// If there are media elements with data-autoplay,
 			// automatically set the autoSlide duration to the
 			// length of that media. Not applicable if the slide
-			// is divided up into fragments. 
+			// is divided up into fragments.
 			// playbackRate is accounted for in the duration.
 			if( currentSlide.querySelectorAll( '.fragment' ).length === 0 ) {
 				toArray( currentSlide.querySelectorAll( 'video, audio' ) ).forEach( function( el ) {
@@ -4113,12 +4262,7 @@
 
 		// Check if the pressed key is question mark
 		if( event.shiftKey && event.charCode === 63 ) {
-			if( dom.overlay ) {
-				closeOverlay();
-			}
-			else {
-				showHelp( true );
-			}
+			toggleHelp();
 		}
 
 	}
@@ -4816,9 +4960,6 @@
 		navigatePrev: navigatePrev,
 		navigateNext: navigateNext,
 
-		// Shows a help overlay with keyboard shortcuts
-		showHelp: showHelp,
-
 		// Forces an update in slide layout
 		layout: layout,
 
@@ -4831,6 +4972,9 @@
 		// Returns an object with the available fragments as booleans (prev/next)
 		availableFragments: availableFragments,
 
+		// Toggles a help overlay with keyboard shortcuts
+		toggleHelp: toggleHelp,
+
 		// Toggles the overview mode on/off
 		toggleOverview: toggleOverview,
 
@@ -4853,12 +4997,19 @@
 		getState: getState,
 		setState: setState,
 
+		// Presentation progress
+		getSlidePastCount: getSlidePastCount,
+
 		// Presentation progress on range of 0-1
 		getProgress: getProgress,
 
 		// Returns the indices of the current, or specified, slide
 		getIndices: getIndices,
 
+		// Returns an Array of all slides
+		getSlides: getSlides,
+
+		// Returns the total number of slides
 		getTotalSlides: getTotalSlides,
 
 		// Returns the slide element at the specified index
diff --git a/static/reveal.js/node_modules/.bin/grunt b/static/reveal.js/node_modules/.bin/grunt
deleted file mode 120000
index 2016eff..0000000
--- a/static/reveal.js/node_modules/.bin/grunt
+++ /dev/null
@@ -1 +0,0 @@
-../../../grunt-cli/bin/grunt
\ No newline at end of file
diff --git a/static/reveal.js/node_modules/.bin/mustache b/static/reveal.js/node_modules/.bin/mustache
deleted file mode 120000
index a71e37a..0000000
--- a/static/reveal.js/node_modules/.bin/mustache
+++ /dev/null
@@ -1 +0,0 @@
-../../../mustache/bin/mustache
\ No newline at end of file
diff --git a/static/reveal.js/package.json b/static/reveal.js/package.json
index 1f866ea..eaec2b2 100644
--- a/static/reveal.js/package.json
+++ b/static/reveal.js/package.json
@@ -1,13 +1,14 @@
 {
   "name": "reveal.js",
-  "version": "3.4.1",
+  "version": "3.5.0",
   "description": "The HTML Presentation Framework",
   "homepage": "http://lab.hakim.se/reveal-js",
   "subdomain": "revealjs",
   "main": "js/reveal.js",
   "scripts": {
     "test": "grunt test",
-    "start": "grunt serve"
+    "start": "grunt serve",
+    "build": "grunt"
   },
   "author": {
     "name": "Hakim El Hattab",
@@ -21,15 +22,11 @@
   "engines": {
     "node": ">=4.0.0"
   },
-  "dependencies": {
-    "express": "~4.14.0",
-    "grunt-cli": "~1.2.0",
-    "mustache": "~2.2.1",
-    "socket.io": "^1.4.8"
-  },
   "devDependencies": {
+    "express": "~4.14.0",
     "grunt": "~1.0.1",
     "grunt-autoprefixer": "~3.0.3",
+    "grunt-cli": "~1.2.0",
     "grunt-contrib-connect": "~0.11.2",
     "grunt-contrib-cssmin": "~0.14.0",
     "grunt-contrib-jshint": "~0.11.3",
@@ -39,7 +36,9 @@
     "grunt-sass": "~1.2.0",
     "grunt-retire": "~0.3.10",
     "grunt-zip": "~0.17.1",
-    "node-sass": "~3.13.0"
+    "mustache": "~2.2.1",
+    "node-sass": "~3.13.0",
+    "socket.io": "^1.4.8"
   },
   "license": "MIT"
 }
diff --git a/static/reveal.js/plugin/markdown/markdown.js b/static/reveal.js/plugin/markdown/markdown.js
index 29aabf5..d9ff1ba 100755
--- a/static/reveal.js/plugin/markdown/markdown.js
+++ b/static/reveal.js/plugin/markdown/markdown.js
@@ -31,7 +31,8 @@
 	 */
 	function getMarkdownFromSlide( section ) {
 
-		var template = section.querySelector( 'script' );
+		// look for a <script> or <textarea data-template> wrapper
+		var template = section.querySelector( '[data-template]' ) || section.querySelector( 'script' );
 
 		// strip leading whitespace so it isn't evaluated as code
 		var text = ( template || section ).textContent;
diff --git a/static/reveal.js/plugin/math/math.js b/static/reveal.js/plugin/math/math.js
index c0a691d..e3b4089 100755
--- a/static/reveal.js/plugin/math/math.js
+++ b/static/reveal.js/plugin/math/math.js
@@ -7,7 +7,7 @@
 var RevealMath = window.RevealMath || (function(){
 
 	var options = Reveal.getConfig().math || {};
-	options.mathjax = options.mathjax || 'https://cdn.mathjax.org/mathjax/latest/MathJax.js';
+	options.mathjax = options.mathjax || 'https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.0/MathJax.js';
 	options.config = options.config || 'TeX-AMS_HTML-full';
 
 	loadScript( options.mathjax + '?config=' + options.config, function() {
diff --git a/static/reveal.js/plugin/notes/notes.html b/static/reveal.js/plugin/notes/notes.html
index 4fda869..e368a5f 100644
--- a/static/reveal.js/plugin/notes/notes.html
+++ b/static/reveal.js/plugin/notes/notes.html
@@ -82,6 +82,7 @@
 				}
 
 				.speaker-controls-time .label,
+				.speaker-controls-pace .label,
 				.speaker-controls-notes .label {
 					text-transform: uppercase;
 					font-weight: normal;
@@ -90,7 +91,7 @@
 					margin: 0;
 				}
 
-				.speaker-controls-time {
+				.speaker-controls-time, .speaker-controls-pace {
 					border-bottom: 1px solid rgba( 200, 200, 200, 0.5 );
 					margin-bottom: 10px;
 					padding: 10px 16px;
@@ -111,6 +112,13 @@
 				.speaker-controls-time .timer,
 				.speaker-controls-time .clock {
 					width: 50%;
+				}
+
+				.speaker-controls-time .timer,
+				.speaker-controls-time .clock,
+				.speaker-controls-time .pacing .hours-value,
+				.speaker-controls-time .pacing .minutes-value,
+				.speaker-controls-time .pacing .seconds-value {
 					font-size: 1.9em;
 				}
 
@@ -124,7 +132,23 @@
 				}
 
 				.speaker-controls-time span.mute {
-					color: #bbb;
+					opacity: 0.3;
+				}
+
+				.speaker-controls-time .pacing-title {
+					margin-top: 5px;
+				}
+
+				.speaker-controls-time .pacing.ahead {
+					color: blue;
+				}
+
+				.speaker-controls-time .pacing.on-track {
+					color: green;
+				}
+
+				.speaker-controls-time .pacing.behind {
+					color: red;
 				}
 
 				.speaker-controls-notes {
@@ -276,6 +300,11 @@
 					<span class="hours-value">00</span><span class="minutes-value">:00</span><span class="seconds-value">:00</span>
 				</div>
 				<div class="clear"></div>
+
+				<h4 class="label pacing-title" style="display: none">Pacing – Time to finish current slide</h4>
+				<div class="pacing" style="display: none">
+					<span class="hours-value">00</span><span class="minutes-value">:00</span><span class="seconds-value">:00</span>
+				</div>
 			</div>
 
 			<div class="speaker-controls-notes hidden">
@@ -450,6 +479,47 @@
 
 				}
 
+				function getTimings() {
+
+					var slides = Reveal.getSlides();
+					var defaultTiming = Reveal.getConfig().defaultTiming;
+					if (defaultTiming == null) {
+						return null;
+					}
+					var timings = [];
+					for ( var i in slides ) {
+						var slide = slides[i];
+						var timing = defaultTiming;
+						if( slide.hasAttribute( 'data-timing' )) {
+							var t = slide.getAttribute( 'data-timing' );
+							timing = parseInt(t);
+							if( isNaN(timing) ) {
+								console.warn("Could not parse timing '" + t + "' of slide " + i + "; using default of " + defaultTiming);
+								timing = defaultTiming;
+							}
+						}
+						timings.push(timing);
+					}
+					return timings;
+
+				}
+
+				/**
+				 * Return the number of seconds allocated for presenting
+				 * all slides up to and including this one.
+				 */
+				function getTimeAllocated(timings) {
+
+					var slides = Reveal.getSlides();
+					var allocated = 0;
+					var currentSlide = Reveal.getSlidePastCount();
+					for (var i in slides.slice(0, currentSlide + 1)) {
+						allocated += timings[i];
+					}
+					return allocated;
+
+				}
+
 				/**
 				 * Create the timer and clock and start updating them
 				 * at an interval.
@@ -457,28 +527,78 @@
 				function setupTimer() {
 
 					var start = new Date(),
-						timeEl = document.querySelector( '.speaker-controls-time' ),
-						clockEl = timeEl.querySelector( '.clock-value' ),
-						hoursEl = timeEl.querySelector( '.hours-value' ),
-						minutesEl = timeEl.querySelector( '.minutes-value' ),
-						secondsEl = timeEl.querySelector( '.seconds-value' );
+					timeEl = document.querySelector( '.speaker-controls-time' ),
+					clockEl = timeEl.querySelector( '.clock-value' ),
+					hoursEl = timeEl.querySelector( '.hours-value' ),
+					minutesEl = timeEl.querySelector( '.minutes-value' ),
+					secondsEl = timeEl.querySelector( '.seconds-value' ),
+					pacingTitleEl = timeEl.querySelector( '.pacing-title' ),
+					pacingEl = timeEl.querySelector( '.pacing' ),
+					pacingHoursEl = pacingEl.querySelector( '.hours-value' ),
+					pacingMinutesEl = pacingEl.querySelector( '.minutes-value' ),
+					pacingSecondsEl = pacingEl.querySelector( '.seconds-value' );
+
+					var timings = getTimings();
+					if (timings !== null) {
+						pacingTitleEl.style.removeProperty('display');
+						pacingEl.style.removeProperty('display');
+					}
+
+					function _displayTime( hrEl, minEl, secEl, time) {
+
+						var sign = Math.sign(time) == -1 ? "-" : "";
+						time = Math.abs(Math.round(time / 1000));
+						var seconds = time % 60;
+						var minutes = Math.floor( time / 60 ) % 60 ;
+						var hours = Math.floor( time / ( 60 * 60 )) ;
+						hrEl.innerHTML = sign + zeroPadInteger( hours );
+						if (hours == 0) {
+							hrEl.classList.add( 'mute' );
+						}
+						else {
+							hrEl.classList.remove( 'mute' );
+						}
+						minEl.innerHTML = ':' + zeroPadInteger( minutes );
+						if (hours == 0 && minutes == 0) {
+							minEl.classList.add( 'mute' );
+						}
+						else {
+							minEl.classList.remove( 'mute' );
+						}
+						secEl.innerHTML = ':' + zeroPadInteger( seconds );
+					}
 
 					function _updateTimer() {
 
 						var diff, hours, minutes, seconds,
-							now = new Date();
+						now = new Date();
 
 						diff = now.getTime() - start.getTime();
-						hours = Math.floor( diff / ( 1000 * 60 * 60 ) );
-						minutes = Math.floor( ( diff / ( 1000 * 60 ) ) % 60 );
-						seconds = Math.floor( ( diff / 1000 ) % 60 );
 
 						clockEl.innerHTML = now.toLocaleTimeString( 'en-US', { hour12: true, hour: '2-digit', minute:'2-digit' } );
-						hoursEl.innerHTML = zeroPadInteger( hours );
-						hoursEl.className = hours > 0 ? '' : 'mute';
-						minutesEl.innerHTML = ':' + zeroPadInteger( minutes );
-						minutesEl.className = minutes > 0 ? '' : 'mute';
-						secondsEl.innerHTML = ':' + zeroPadInteger( seconds );
+						_displayTime( hoursEl, minutesEl, secondsEl, diff );
+						if (timings !== null) {
+							_updatePacing(diff);
+						}
+
+					}
+
+					function _updatePacing(diff) {
+
+						var slideEndTiming = getTimeAllocated(timings) * 1000;
+						var currentSlide = Reveal.getSlidePastCount();
+						var currentSlideTiming = timings[currentSlide] * 1000;
+						var timeLeftCurrentSlide = slideEndTiming - diff;
+						if (timeLeftCurrentSlide < 0) {
+							pacingEl.className = 'pacing behind';
+						}
+						else if (timeLeftCurrentSlide < currentSlideTiming) {
+							pacingEl.className = 'pacing on-track';
+						}
+						else {
+							pacingEl.className = 'pacing ahead';
+						}
+						_displayTime( pacingHoursEl, pacingMinutesEl, pacingSecondsEl, timeLeftCurrentSlide );
 
 					}
 
@@ -488,9 +608,26 @@
 					// Then update every second
 					setInterval( _updateTimer, 1000 );
 
-					timeEl.addEventListener( 'click', function() {
-						start = new Date();
+					function _resetTimer() {
+
+						if (timings == null) {
+							start = new Date();
+						}
+						else {
+							// Reset timer to beginning of current slide
+							var slideEndTiming = getTimeAllocated(timings) * 1000;
+							var currentSlide = Reveal.getSlidePastCount();
+							var currentSlideTiming = timings[currentSlide] * 1000;
+							var previousSlidesTiming = slideEndTiming - currentSlideTiming;
+							var now = new Date();
+							start = new Date(now.getTime() - previousSlidesTiming);
+						}
 						_updateTimer();
+
+					}
+
+					timeEl.addEventListener( 'click', function() {
+						_resetTimer();
 						return false;
 					} );
 
diff --git a/static/reveal.js/plugin/notes/notes.js b/static/reveal.js/plugin/notes/notes.js
index 88f98d6..80fb6e2 100644
--- a/static/reveal.js/plugin/notes/notes.js
+++ b/static/reveal.js/plugin/notes/notes.js
@@ -21,6 +21,9 @@ var RevealNotes = (function() {
 
 		var notesPopup = window.open( notesFilePath, 'reveal.js - Notes', 'width=1100,height=700' );
 
+		// Allow popup window access to Reveal API
+		notesPopup.Reveal = this.Reveal;
+
 		/**
 		 * Connect to the notes window through a postmessage handshake.
 		 * Using postmessage enables us to work in situations where the
@@ -50,10 +53,11 @@ var RevealNotes = (function() {
 		/**
 		 * Posts the current slide data to the notes window
 		 */
-		function post() {
+		function post( event ) {
 
 			var slideElement = Reveal.getCurrentSlide(),
-				notesElement = slideElement.querySelector( 'aside.notes' );
+				notesElement = slideElement.querySelector( 'aside.notes' ),
+				fragmentElement = slideElement.querySelector( '.current-fragment' );
 
 			var messageData = {
 				namespace: 'reveal-notes',
@@ -70,6 +74,21 @@ var RevealNotes = (function() {
 				messageData.whitespace = 'pre-wrap';
 			}
 
+			// Look for notes defined in a fragment
+			if( fragmentElement ) {
+				var fragmentNotes = fragmentElement.querySelector( 'aside.notes' );
+				if( fragmentNotes ) {
+					notesElement = fragmentNotes;
+				}
+				else if( fragmentElement.hasAttribute( 'data-notes' ) ) {
+					messageData.notes = fragmentElement.getAttribute( 'data-notes' );
+					messageData.whitespace = 'pre-wrap';
+
+					// In case there are slide notes
+					notesElement = null;
+				}
+			}
+
 			// Look for notes defined in an aside element
 			if( notesElement ) {
 				messageData.notes = notesElement.innerHTML;
diff --git a/static/reveal.js/plugin/print-pdf/print-pdf.js b/static/reveal.js/plugin/print-pdf/print-pdf.js
index 38a698d..9ffc261 100644
--- a/static/reveal.js/plugin/print-pdf/print-pdf.js
+++ b/static/reveal.js/plugin/print-pdf/print-pdf.js
@@ -4,30 +4,16 @@
  * Example:
  * phantomjs print-pdf.js "http://lab.hakim.se/reveal-js?print-pdf" reveal-demo.pdf
  *
- * By Manuel Bieh (https://github.com/manuelbieh)
+ * @author Manuel Bieh (https://github.com/manuelbieh)
+ * @author Hakim El Hattab (https://github.com/hakimel)
+ * @author Manuel Riezebosch (https://github.com/riezebosch)
  */
 
 // html2pdf.js
-var page = new WebPage();
 var system = require( 'system' );
 
-var slideWidth = system.args[3] ? system.args[3].split( 'x' )[0] : 960;
-var slideHeight = system.args[3] ? system.args[3].split( 'x' )[1] : 700;
-
-page.viewportSize = {
-	width: slideWidth,
-	height: slideHeight
-};
-
-// TODO
-// Something is wrong with these config values. An input
-// paper width of 1920px actually results in a 756px wide
-// PDF.
-page.paperSize = {
-	width: Math.round( slideWidth * 2 ),
-	height: Math.round( slideHeight * 2 ),
-	border: 0
-};
+var probePage = new WebPage();
+var printPage = new WebPage();
 
 var inputFile = system.args[1] || 'index.html?print-pdf';
 var outputFile = system.args[2] || 'slides.pdf';
@@ -36,13 +22,48 @@ if( outputFile.match( /\.pdf$/gi ) === null ) {
 	outputFile += '.pdf';
 }
 
-console.log( 'Printing PDF (Paper size: '+ page.paperSize.width + 'x' + page.paperSize.height +')' );
+console.log( 'Export PDF: Reading reveal.js config [1/4]' );
 
-page.open( inputFile, function( status ) {
-	window.setTimeout( function() {
-		console.log( 'Printed successfully' );
-		page.render( outputFile );
-		phantom.exit();
-	}, 1000 );
+probePage.open( inputFile, function( status ) {
+
+	console.log( 'Export PDF: Preparing print layout [2/4]' );
+
+	var config = probePage.evaluate( function() {
+		return Reveal.getConfig();
+	} );
+
+	if( config ) {
+
+		printPage.paperSize = {
+			width: Math.floor( config.width * ( 1 + config.margin ) ),
+			height: Math.floor( config.height * ( 1 + config.margin ) ),
+			border: 0
+		};
+
+		printPage.open( inputFile, function( status ) {
+			console.log( 'Export PDF: Preparing pdf [3/4]')
+			printPage.evaluate(function() {
+				Reveal.isReady() ? window.callPhantom() : Reveal.addEventListener( 'pdf-ready', window.callPhantom );
+			});
+		} );
+
+		printPage.onCallback = function(data) {
+			// For some reason we need to "jump the queue" for syntax highlighting to work.
+			// See: http://stackoverflow.com/a/3580132/129269
+			setTimeout(function() {
+				console.log( 'Export PDF: Writing file [4/4]' );
+				printPage.render( outputFile );
+				console.log( 'Export PDF: Finished successfully!' );
+				phantom.exit();
+			}, 0);
+		};
+	}
+	else {
+
+        console.log( 'Export PDF: Unable to read reveal.js config. Make sure the input address points to a reveal.js page.' );
+        phantom.exit(1);
+
+    }
 } );
 
+
diff --git a/static/reveal.js/test/examples/math.html b/static/reveal.js/test/examples/math.html
index 1b80e03..d35e827 100644
--- a/static/reveal.js/test/examples/math.html
+++ b/static/reveal.js/test/examples/math.html
@@ -169,7 +169,7 @@
 				transition: 'linear',
 
 				math: {
-					// mathjax: 'http://cdn.mathjax.org/mathjax/latest/MathJax.js',
+					// mathjax: 'https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.0/MathJax.js',
 					config: 'TeX-AMS_HTML-full'
 				},
 
diff --git a/templates/stash.tmpl b/templates/stash.tmpl
index 6399f05..cc9b3e0 100644
--- a/templates/stash.tmpl
+++ b/templates/stash.tmpl
@@ -13,7 +13,7 @@
     <body>
         <div id="stash-pane">
           <div id="controls">
-          <a href="/stash" target="_blank" onclick="save();"> Stash</a> | 
+          <a href="/stash" target="_blank" onclick="save();"> Stash</a> |
             <a href="/published/{{ .pubTo}}" target="_blank" onclick="save();"> Present</a> |
             <a href="/published/{{ .pubTo}}?print-pdf" target="_blank" onclick="save();"> Pdf</a>
           </div>
@@ -33,7 +33,7 @@
           	</table>
           </div>
         </div>
-      
+
         <script src="/static/revealjs/js/ace-1.1.8/ace.js" type="text/javascript" charset="utf-8"></script>
         <script src="/static/revealjs/js/jquery-2.1.3.min.js" type="text/javascript" charset="utf-8"></script>
         <script src="/static/revealjs/js/jquery-debounce-1.0.5.js" type="text/javascript" charset="utf-8"></script>
@@ -42,4 +42,4 @@
     </body>
 </html>
 
-{{ end }}
\ No newline at end of file
+{{ end }}
diff --git a/yarn.lock b/yarn.lock
new file mode 100644
index 0000000..82bd023
--- /dev/null
+++ b/yarn.lock
@@ -0,0 +1,6 @@
+# THIS IS AN AUTOGENERATED FILE. DO NOT EDIT THIS FILE DIRECTLY.
+# yarn lockfile v1
+reveal.js:
+  version "3.5.0"
+  resolved "https://registry.yarnpkg.com/reveal.js/-/reveal.js-3.5.0.tgz#95545949ad682636acecfdaea05cf0ca892d442d"
+