The controller for Buttons. Not meant to be used with buttons that have mouseOver feeback when the button is not pressed. Use mouseEnter/mouseLeave for that.

	button activity
	yellowButtonActivity

	control defaults
	controlActivity isControlActive isControlWanted

	basic control sequence	top
	controlInitialize Provide feedback indicating that button has been entered with the mouse down. If triggerOnMouseDown is true, then do the button action on mouse down--and don't bother with the feedback since the action happens immediately.
	controlTerminate Reverse the feedback displayed by controlInitialize, if any. Perform the button action if necessary.

	button activity	top
	yellowButtonActivity Invoke the model's menu. This is option-click, NOT the normal button press.

	control defaults	top
	controlActivity Pass control to the next control level (that is, to the Controller of a subView of the receiver's view) if possible. It is sent by Controller|controlLoop each time through the main control loop. It should be redefined in a subclass if some other action is needed.
	isControlActive Answer whether receiver wishes to continue evaluating its controlLoop method. It is sent by Controller|controlLoop in order to determine when the receiver's control loop should terminate, and should be redefined in a subclass if some special condition for terminating the main control loop is needed.
	isControlWanted sensor flushKeyboard.