2004-09-14  Sven Neumann  <sven@gimp.org>

	* app/dialogs/dialogs-constructors.[ch]
	* app/dialogs/dialogs.c
	* app/gui/gui.c: let the dialog factory handle the quit dialog
	as singleton. Fixes bug #151914.

	* app/dialogs/quit-dialog.c: added a warning here. We need a
	container of dirty images for the above change to work correctly.