menu elements abstracted

only 'buttons' will be selectable and able to be scrolled through in
menus
will be creating toggle buttons and drop down menus which also follow
this
other items either textured or non textured can be drawn to screen
without interrupting menu navigation

menu state class will eventually be turned in to full abstract class and
just be inherited by any relevant menu states
game will not be responsible for populating menus (especially not in
init as resizing screws up positions)