If the receiver has any kind of button-action defined, fire that action now. Any morph can have special, personal mouseUpCodeToRun, and that will be triggered by this. Additionally, some morphs have specific buttonness, and these get sent the #doButtonAction message to carry out their firing. Finally, some morphs have mouse behaviors associated with one or more Player scripts.
For the present, we'll try out doing *all* the firings this object can do.
Receive a change notice from an object of whom the receiver is a
dependent. The default behavior is to do nothing; a subclass might want
to change itself in some way.
