Scrolling Background with AnimLayer,GameStage and GameStageFront
MovementSpeed of all GameStageLayers can be set indiviual

-Whole Movement, can be called by moveGameStage function
Game Stage is no longer fliped

-Added new Images for GameStage
-AnimLayer is now a container that can hold all kind of animations
Names for the Backgrounds was moved to GameConstants

-Removed player from Game and added him to GameStage
-Modified AssetsNames
-Moved Constants from SoundManager into GameConstants
GameStage is now handled in one container
Scrolling with tree different images
-The two gameStage Container take their content from a List of Images and return not used images into this list
All tree layers are now handlet in Containers
Shortend the GameStage Class
Fixed Some Buges and refarctored the GameStage:

-Movement is working again (only refering to one entityManager)
Merge remote-tracking branch 'refs/remotes/origin/feature/background' into develop
Merge remote-tracking branch 'refs/remotes/origin/develop' into develop