- Moved the build variants descriptions into build_system
- Added Makefile stub into sensors.jd as a starting point
- Small cleanup to build_new_device to reference the PRODUCT_* parameters
- Fixed URL in the README for app engine testing

Conflicts:

	pdk/README
	pdk/docs/guide/build_new_device.jd
	pdk/docs/guide/build_system.jd
	pdk/docs/guide/sensors.jd
diff --git a/pdk/docs/guide/pdk_toc.cs b/pdk/docs/guide/pdk_toc.cs
index f98f194..82f9e86 100644
--- a/pdk/docs/guide/pdk_toc.cs
+++ b/pdk/docs/guide/pdk_toc.cs
@@ -8,11 +8,14 @@
 
 <li> <h2>Setup and Building</h2>
   <ul>
-     <li><a href="<?cs var:toroot ?>guide/system_requirements.html">Device Requirements</a></li>           
-     <li><a href="<?cs var:toroot ?>guide/build_system.html">Build System</a></li>
-     <li><a href="<?cs var:toroot ?>guide/build_new_device.html">Building New Device</a></li>
-     <li><a href="<?cs var:toroot ?>guide/build_cookbook.html">Build Cookbook</a></li>
-     <li><a href="<?cs var:toroot ?>guide/bring_up.html">Bring up</a></li>
+     <li class="toggle-list">
+     <div><a href="<?cs var:toroot ?>guide/build_system.html">Build System</a></div>
+     <ul>  
+       <li><a href="<?cs var:toroot ?>guide/build_new_device.html">Configuring a New Product</a></li>
+       <li><a href="<?cs var:toroot ?>guide/build_cookbook.html">Build Cookbook</a></li>
+       <li><a href="<?cs var:toroot ?>guide/bring_up.html">Bring up</a></li>
+     </ul>
+     </li>
      <li><a href="<?cs var:toroot ?>guide/release_keys.html">Release Keys and Signing Builds</a></li> 
  </ul>
 </li>