shell_tray_manager.c: Add a bg-color property and implement it
by setting a 1x1 pixmap of the right color as the background.
Also, make the colormap of the tray manager window match that
of the socket. That should (untested) make transparency work
properly if the tray icon supports it.
panel.js: Set the bg-color property of the tray manager to
match the panel.
http://bugzilla.gnome.org/show_bug.cgi?id=561872
svn path=/trunk/; revision=82
8a9b138c2e