Move world.step() back down to CoreLogic

[ntpeters]

Figure out if there is a way to get the world.step() call working in CoreLogic, as all of the back-end logic should ideally be handled there.

[krgauthi]

@Rinkus in game screen corelogic.execute is called in handle input this execute command handles input and logic I would make a separate method to handle the input/updating logic then when the method is called once every frame in gamescreen update you can call world step and compute other logic for warping destroying and spawning entities

[krgauthi]

This is implemented in my next pull request.