MDI-Tab-Position patch

[Mathias Hasselmann <mathias hasselmann gmx de>]

Hi,

        Bored by seeing galeon2's and gnome-terminal's tabs on top of the
MDI window i decided to create a patch fixing this problem. The resulting
code introduces a GConf key "/desktop/gnome/interface/mdi_tab_position",
updates gnome-ui-properties, introduces gnome_add_setup_mdi_notebook in
libgnomeui/gnome-app-helper.h.

        This work is available as bug 85504 in bugzilla
(http://bugzilla.gnome.org/show_bug.cgi?id=85504).
                                                                                                    
Still questionary:
                                                                                                            
- should there really be the "preferred MDI style" entry in
          gnome-ui-properties -- it's easy to remove th
        - is gnome-ui-properties the right capplet, should it get a
          notebook-interface, should the MDI stuff go i
                                                                                                    
Rationale:
                                                                                                            
Guess it's perception thing (as for the buttons in dialogs): When
surfing with galeon I personally use the tabs to download pages in the
packground. When using the terminal I'm putting related background tasks
into other tabs. Background is the keyword in both use cases: The
existence of the tabs is an important convenience feature, keeps the
desktop uncluttered... But the tasks running in them are background tasks,
they are not important for my current workflow, placed at the top with all
the important control elements (location field, back/forward/reload-
button) the tabs are disturbing, gaining far too much perception. So I
like to have them at the bottom. The idea is: I only have one pair of
eyes, one pair of hands so I only can use on tab at the moment. The other
tabs are nice to exists and it's important that they are easy to access,
_but_ they shall not disturb my perception.