* app/apptypes.h
* app/pathsP.h: removed trailing enum commas

* app/gdisplay_color.[ch]: added a foreach function to iterate
over the display filter names

* app/gdisplay_color_ui.[ch]: display filter ui stuff (doesn't do
much yet ;)

* app/commands.[ch]
* app/menus.c: hooked the above into the menu system

* app/Makefile.am: added new files

* plug-ins/gimpressionist/preview.c: removed bogus // comment

-Yosh