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

* commit '41b4a286c98ded1dbb8bf2fcdd5a9ca29f9423e2':
  Add package-level documentation referencing the guide.

Change-Id: I6b4ca4f319316acd77adbde7678ea512d1550299