Add package-level documentation referencing the guide. am: 52c473f am: 84dc2cd am: 41b4a28 am: c994188
am: bf48006

* commit 'bf4800613e1c724a1dd7de7a0e9733e6ec7716dd':
  Add package-level documentation referencing the guide.

Change-Id: I652e9641b6b803021eddd4c93cdd699a2515b18c