Added introductory tables to Chrome apps APIs.

chrome/common/extensions/docs/templates/intros/commands.html

-<p>
-The commands API allows you to add keyboard shortcuts that trigger actions in
-your extension. An action can be opening the browser action or page action popup
-or sending a command to the extension.
-</p>
+<table class="intro">
+  <tr>
+    <th scope="col"></th>
+    <th scope="col"></th>
+  </tr>
+  <tr>
+    <td><strong>Description:</strong></td>
+    <td>Use the commands API to add keyboard shortcuts
+    that trigger actions in your extension,
+    for example, an action to open the browser action
+    or send a command to the extension.</td>
+  </tr>
+  <tr>
+    <td><strong>Availability:</strong></td>
+    <td>On target to be stable in Chrome 25</td>

[saroop, 2012/12/21 00:39:44]

On target seems confusing .. shall we say devchannel and update it to stable
once it hits stable ?

+  </tr>
+  <tr>
+    <td><strong>Permissions:</strong></td>
+    <td>None</td>
+  </tr>
+</table>
 
 <h2 id="manifest">Manifest</h2>
 <p>
 You must set manifest_version to (at least) 2 to use this API.
 </p>
 
 <h2 id="usage">Usage</h2>
 <p>The commands API allows you to define specific commands, and bind them to a
 default key combination. Each command your extension accepts must be listed in
 the manifest as an attribute of the 'commands' manifest key. Note: Combinations
@@ skipping 40 matching lines @@
   console.log('Command:', command);
 });
 </pre>
 
 <p>The '_execute_browser_action' and '_execute_page_action' commands are
 reserved for the action of opening your extension's popups. They won't normally
 generate events that you can handle. If you need to take action based on your
 popup opening, consider listening for an 'onDomReady' event inside your popup's
 code.
 </p>