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

* commit 'c9941884496ab55fbe617bb24da4531004ab52ce':
  Add package-level documentation referencing the guide.

Change-Id: I434432cdf27f2db44757f38fe31a85d7b106b22b