Took out scenemanager from the eventloop and window.

Replaced this with the MainGame class,
This class should be used to manage everything,
Scenemanager ,inputmanager, assetmanager,...
So everything comes together in here so far.
Added a testscene that derives from the basescene, and is activated in the beginning of the program.
Works both on windows and android.
eventloop was not commited