Fixes #866
Removing the erroneous if statement around drawing a control's background allows there to be
borders only on some sides of a skinned control.
Using NEAREST filter instead of LINEAR on theme textures to fix blurry borders.
Fixes a typo in ImageControl's UV calculations.
Allows opacity to affect ImageControls.
Merge branch 'next' of https://github.com/blackberry/GamePlay into bugfix
Merge pull request #911 from ablake/next

More small UI bug fixes.
Allows container opacity to be animated by using the correct property for the scrollbar animations.
Merge branch 'next' of https://github.com/blackberry/GamePlay into bugfix
Merge pull request #916 from ablake/next

Quick fix for animating Container opacity.
Fixing upside-down "full image" UVs used as defaults.
Merge pull request #917 from ablake/next

Fixing upside-down "full image" UVs used as defaults.
Initial code for Sprite.
Enables controlling UI forms with a gamepad.  Adds a few things to the forms test in order to test
this feature.
Merge branch 'next' of https://github.com/blackberry/GamePlay into next

Conflicts:
	gameplay/src/Control.cpp
Allows ImageControls to act as buttons.
Merge branch 'bugfix' of https://github.com/ablake/GamePlay into bugfix
Add the TileSheet files.
Merge branch 'next' of git://github.com/blackberry/GamePlay into twoD_additions
Changed ScriptController::loadScript() to use dofile instead of dostring.
- This will give more informative error messages that will tell you the file and line number the error occurred at.
- However, Android will still use dostring because dofile does not work on files in the resource APK.
Just the basics to create a TileSheet.
Made sure that when Node clones itself, it clone's Sprite as well.
Implemented basics of cloning for Sprite.
Added create functions to Sprite.
Added get/setSprite to Lua Node.