Detail markdown plugin attributes & defaults

Expands the details already given by highlighting the defaults for all attributes and clarifying what's required.

README.md

@@ -105,7 +105,7 @@ 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 `<script type="text/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).
 
@@ -121,9 +121,9 @@ This is based on [data-markdown](https://gist.github.com/1343518) from [Paul Iri
 
 #### External Markdown
 
-You can write your content as a separate file and have reveal.js load it at runtime. Note the separator arguments which determine how slides are delimited in the external file. The ```data-charset``` attribute is optional and specifies which charset to use when loading the external file.
+You can write your content as a separate file and have reveal.js load it at runtime. Note the separator arguments which determine how slides are delimited in the external file: the `data-separator` attribute defines a regular expression for horizontal slides (defaults to `^\r?\n---\r?\n$`, a newline-bounded horizontal rule)  and `data-separator-vertical` defines vertical slides (disabled by default). The `data-separator-notes` attribute is a regular expression for specifying the beginning of the current slide's speaker notes (defaults to `note:`). The `data-charset` attribute is optional and specifies which charset to use when loading the external file.
 
-When used locally, this feature requires that reveal.js [runs from a local web server](#full-setup).
+When used locally, this feature requires that reveal.js [runs from a local web server](#full-setup).  The following example customises all available options:
 
 ```html
 <section data-markdown="example.md"