Add LifecycleTest for the Assistant
Verify that firing the Assistant does not trigger lifecycle methods
such as onPause(),onStop(), etc to be called by the foregroud activity.
Refactored tests to make use of BroadcastReceivers for more fine grained
control of when the Assistant is shown and hidden.
Added Content View for the assistant.

Change-Id: I7692e687df7c3aa5970a2717e82385bb852648d4
16 files changed