GameScreen optimisation

Renamed Box2DTiledMapParserTest to GameScreen
Renamed PixelScreen to PixelGameScreen
Moved default actions from GameScreen to PixelGameScreen
Player Optimisation

Removed useless comments
Renamed PlayerAnimation
Begin to port PlayerAnimationHandler to better logic and jsonhandler
Moved Player Animator

Moved PlayerAnimatorHandler to handlers package
Merge branch 'master' into Optimisation

Conflicts:
	core/src/com/FOS/Pixel/Box2DTiledMapParserTest.java
	core/src/com/FOS/Pixel/Player.java
	core/src/com/FOS/Pixel/handlers/PlayerAnimatorHandler.java
Merge branch 'Optimisation'