Contact picker: add search icon & hide searchview

Hide/unhide the SearchView when you click a seach menu item.
This is the first and more important step for b/16190113.

In a later CL, I might remove the SearchView and replace it
with the custom actionbar view created by dialer & used
in PeopleActivity.

Also merged JoinContactActivity into ContactSelectionActivity.

Bug: 16190113
Change-Id: I04bf7d22dffbf7f104362b17c9064cb386a01abe