1999-03-27  Michael Natterer  <mitschel@cs.tu-berlin.de>

        * app/brush_select.c
        * app/channels_dialog.c
        * app/color_select.c
        * app/devices.c
        * app/file_new_dialog.c
        * app/gradient_select.c
        * app/palette_select.c
        * app/pattern_select.c: applied a patch from Marco Lamberto
        <lm@geocities.com> which unifies actionareas ("Cancel" rightmost
        and default). Did the same in some more dialogs.

        * libgimp/gimpfileselection.c
        * libgimp/gimppatheditor.c
        * app/preferences_dialog.[ch]: completely reworked the preferences
        dialog:

        - select the notebook's pages with a tree.
        - reordered the categories. Please give me feedback, this really
          needs to be intuitive.
        - removed lots of unused #include's.
        - turned the prefs. dialog into a test site for new convenience
          constructors. These changes are...