split custom window methods and properties from Game into Display

[tsedan]

as the title says, we want to access window information and properties not through Game (which is super cluttered and not following OOP) but through the Display class. This means porting all the current Game window methods into Display and refactoring code to work with these new changes.

Preferably we could also have separate getters and setters for the window size and the display width/height so that users don't have to mess with unintuitive sounding variables like "resolution".