* SceneManager, Scene, Layer, GameHelper classes are added to project.
* The classes BackgroundLayer, GameLayer, UILayer, which are derived from Layer class, are created and the object added to the game Scene.as
* For the beginning there is only one scene called GameScene. MenuScene will be added later on.

Signed-off-by: Baris Yilmaz <baris.yilmaz.1985@gmail.com>