Made it significantly easier to add new menu items to a menu.
Added buttonHeight and buttonWidth to Constants
MenuItem now takes position as an argument instead of coordinates for a bounding box
Updated constructors in the individual menus
Overloading constructor in MenuItem. Now possible to toggle playerCount. Added INITIAL_PLAYER_COUNT in Constants
Implemented data in MenuItem. Will be drawn on screen and can be set with setter and in constructor.
Using overloaded constructor, it is not needed to add data to a menu item
Merge branch 'Menus'

Conflicts:
	game/src/no/ntnu/folk/game/Constants.java