xdg-desktop-menu: Drop obsolete GNOME support
Closes #81
Seeing that unnecessary ~/.gnome is a pet peeve of mine. Hopefully this saves you a bit of work. Original message:
This commit drops the obsolete support for the GNOME-specific directory for .desktop files, since it has not been needed since GNOME 2.10, and since it forces the creation of ~/.gnome whether you want it or not.