Removes the need for games to call update() on forms and gamepads each frame,
and removes these calls from all tests and samples.
Also adds a few private methods to Gamepad in preparation for enabling gamepad control of UI forms.
Missed some changes to Form.cpp in previous commit.
Issue #841
Adds a very basic ImageControl class for including png images in UI forms.
Basic test of ImageControl.
Merge branch 'next' of https://github.com/blackberry/GamePlay into next
Merge pull request #887 from ablake/next

Next