Mon Aug 23 10:15:32 EDT 1999  Austin Donnelly  <austin@gimp.org>

	Dirty flag now correct in all cases.  Can be displayed in image
	window title too.  See NOTE near gimp_image_dirty() for details.

	* app/fileops.c: gimp_image_clean_all() after reverting an image.
	* app/gdisplay.c: register handlers for gimage dirty and clean
	    signals to update image title.  New image-title-format
	    expansion: %Dx expands to x if the image is dirty.
	* app/gdisplay_ops.c: gimage->dirty flags != 0 is the correct
	    condition to test to see if an image is dirty.
	* app/gimpdrawable.c: gimp_image_dirty() should never be called
	    except from an undo_push_* function.  Call
	    undo_push_cantundo() if you want to dirty the image but can't
	    be bothered writing an undo handler (be ashamed of yourself!).
	* app/gimpimage.c: new gimage signal: clean.  Emitted when an undo
	    operation takes place.  Gimage changes when either dirty or
	    clea...