Advances search results pager on POI item cick.

* Removes PoiLayer class; migrates gesture listener into MapFragment.
* Extracts FakeMotionEvent class for reuse.
* Moves TestHelper into support package.
* Moves MapzenTestRunner into support package.
* Adds OnPoiClickListener.
* Shows current search result on POI pin cilck.
* Does not reset zoom when advancing through search results.