* libgimp/gimpexport.c: get rid of remaining (invisible) layers
        after merging visible layers

        * app/channel_ops.[ch]: applied a patch from Garry R. Osgood that
	seems to fix bugs #2261 and #2382 (crashes when using offset).
        A few more changes made the dialog actually work...

        * app/ops_buttons.c: plugged a memleak I introduced yesterday

--Sven