Gestures

Some gesture support
* Adds long press and double tap to libFrank and frank-cucumber
* Adds long press and double tap views to the Controls test app
* Add tests for long press and double tap to the Controls test app
* Fixes a bug in the tables test in the Controls test app

Trying to follow the UIAElement reference as close as possible for the apis.
Also, im new to ruby so my code may not be idiomatic but i've tried to keep it clean.