#1 gconf-replacement with real wallpaper for unstable

[onli]

Relying solely on gconf for detecting the currently used wallpaper is not sufficent, e.g. on my system the wallpaper is set using Esetroot very often. The patch replaces the gconf-approach with wnck_screen_get_background_pixmap(WnckScreen), which should work everywhere.

The patch was created using svn diff against unstable, hope that is ok. As it is larger than the 256k, i pasted it here: http://paste.ubuntuusers.de/400802/