Fixing kdesk wallpaper mode (-w parameter)

 o Fixed an error where the wallpaper set mode
   was not permanent, so dragging a window along the
   root background space would clear out the wallpaper image.
   Enforcing the wallpaper image to stay in the root window's map space.
Merge pull request #33 from KanoComputing/fix-background

Fixing kdesk wallpaper mode (-w parameter)