API issues
	+ need a dispose on the bonobo_listener
	+ need a bonobo_object_query_remote
	+ need to allow custom POAs for object construction,
	  a construct time property ?

UI stuff - need a CORBA_Object bonobo_widget_query_interface () method.
publicize bonobo_socket_add_id.

	+ hide / deprecate BonoboUINode
	+ create & use bonobo_ui_engine_peek_attr