Undo the effects of the wrapped Action.

	undoing
	undoIt

	accessing	top
	rectifyActorClassesInBlocks UndoAction allInstancesDo: [:ua | ua rectifyActorClassesInBlocks]
	setAction: Specify the undo action to wrap.

	undoing	top
	undoIt Undo the wrapped action

	instance creation	top
	new: Create a wrapper for undoing an animation