Engine nearly finished, everything is now working!

- Added engine:refeshEntity to Collisions
- Removed Debugcode from gameOverState
- Fixed Backgroundentity in levelOneState
- Fixed typo in engine:removeEntity()
- fixed bug in engine:removeEntity()
- fixed bug in engine:refreshEntity()
- removed Debugcode in MineProximitySystem:update()
- I wrote a workaround for engine:getEntitylist(component) for not existing Entitylists.
       Every component has a own table in engine and every entity that contains this component
       is listed in those table.