hotkeys: implement a-prefix hotkeys (a i, a u, a a, a n)

help/3.php

@@ -38,6 +38,15 @@
 
 	</td><td valign='top'>
 
+	<h2><?php echo __("Multiple articles actions") ?></h2>
+
+	<table>
+		<tr><td class='n'>a a</td><td><?php echo __("Select all articles") ?></td></tr>
+		<tr><td class='n'>a u</td><td><?php echo __("Select unread articles") ?></td></tr>
+		<tr><td class='n'>a i</td><td><?php echo __("Invert article selection") ?></td></tr>
+		<tr><td class='n'>a n</td><td><?php echo __("Deselect all articles") ?></td></tr>
+	</table>
+
 	<h2><?php echo __("Feed actions") ?></h2>
 
 	<table>

tt-rss.js

@@ -654,7 +654,7 @@ function hotkey_handler(e) {
 		if (keycode == 16) return; // ignore lone shift
 		if (keycode == 17) return; // ignore lone ctrl
 
-		if ((keycode == 70 || keycode == 67 || keycode == 71)
+		if ((keycode == 70 || keycode == 67 || keycode == 71 || keycode == 65)
 				&& !hotkey_prefix) {
 
 			var date = new Date();
@@ -766,7 +766,6 @@ function hotkey_handler(e) {
 				return;
 			}
 
-
 			if (keycode == 85) { // u
 				selectionToggleUnread(undefined, false, true)
 				return;
@@ -815,6 +814,33 @@ function hotkey_handler(e) {
 			}
 		}
 
+		/* Prefix a */
+
+		if (hotkey_prefix == 65) { // a
+			hotkey_prefix = false;
+
+			if (keycode == 65) { // a
+				selectArticles('all');
+				return;
+			}
+
+			if (keycode == 85) { // u
+				selectArticles('unread');
+				return;
+			}
+
+			if (keycode == 73) { // i
+				selectArticles('invert');
+				return;
+			}
+
+			if (keycode == 78) { // n
+				selectArticles('none');
+				return;
+			}
+
+		}
+
 		/* Prefix f */
 
 		if (hotkey_prefix == 70) { // f