Add package-level documentation referencing the guide. am: 52c473f am: 84dc2cd am: 41b4a28
am: c4f8ab6

* commit 'c4f8ab6c6945e55e0182f588cae94cd43ba0288c':

Change-Id: Id5cdd711ec30497755f9e2efd0a7d9118c16ae54