Design Overview
	Keyboard Arguments
		All buttons up at once or separated into groups (capital, lowercase etc)?
	How do we undo deletions?
		Images aren't deleted when you say "delete"
		They're hidden, and remember how they look
		On the next undoable action, "whack it"
		Problem: a lot of complex notifications are going to be flung around.
		Solution: The Action Stack to just keep the last undoable action
			To extend the number of undos, make the stack larger than one undo.
	Subclassing the Actions
		What constitutes a Transform Action, or Collage-level actions
			Transformations on the image?
	Mousedown and Hold events
		We have a mouse down, a mouse up and a mouse move event
		Should there be a timer for a hold event?
		There is no special case for button down, why not treat it like a drag?
			Pro:
				Simplifies design
				Good for development
			Con:
				Have to worry about not redrawing images if they're moved to the same place