Removing the Multimedia Systems Selector from the menus

[Bastien Nocera <hadess hadess net>]

Heya,

Now that GStreamer is tip-top at autodetection, I think we should remove
the "gstreamer-properties" from the menus, and leave the binary
installed as a debug tool.

Would this break any documentation (apart from debug documentation,
obviously...)

Patch and bug are at:
http://bugzilla.gnome.org/show_bug.cgi?id=408292

Cheers