Move icons in source tree (plus emblems/backgrounds dialog request)

[Luca Ferretti <elle uca libero it>]

About one year ago, I've added the Nautilus icon under
nautilus/icons/appicon/ directory.

It's OK to move it under data/ directory to match the layout of other
GNOME projects?

The final result will be something like:

        nautilus +
                 |
                 + data +
                        |
                        + icons +
                                |
                                + 16x16 +
                                |       |
                                |       + apps
                                |
                                + 22x22 +
                                        |
                                        + apps

PS here is someone able to rewrite the emblem/background dialog to use
named icons for buttons? We have Tango icons, but the current code grabs
the pixmap from a XML file :-( Of course a re-design to match GNOME HIG
could be better...

PPS meanwhile, it's OK to replace backgrounds.png emblems.png and
colors.png inside nautilus/icons with the Tango version available in bug
374722