Some new button stuff vDETAILSv

- The "assigning" sheets are animations that, I'm now thinking, would be
cool if played while controller is detected but player hasn't yet joined
by pressing A ("A" button and "Join" can be placed beneath "assigning"
animation for example)

- Also, the "buttons" sheets are all in clockwise order starting with
the bottom middle button, for simplicity's sake.

- Next, some (just a few) key/mouse icons!