* libnautilus-extensions/nautilus-mime-actions.h,
	* libnautilus-extensions/nautilus-mime-actions.c:
	(nautilus_mime_add_application_to_short_list_for_uri),
	(nautilus_mime_remove_application_from_short_list_for_uri),
	(nautilus_mime_add_component_to_short_list_for_uri),
	(nautilus_mime_remove_component_from_short_list_for_uri):
	New prototypes and empty function bodies, convenience
	covers for modifying the short lists. Not yet implemented,
	but callable.

	* libnautilus-extensions/nautilus-program-chooser.c:
	(add_to_short_list_for_file), (remove_from_short_list_for_file),
	(add_to_short_list_for_type), (remove_from_short_list_for_type),
	(run_program_configurator_callback): Wired up things so if
	the user switches radio buttons in the "Modify details" dialog,
	the right code is called when they hit OK. But this right code
	doesn't yet do anything.