We can autodetect what to do based on the user's session, so drop
the separate desktop files.
This, along with some future changes, will enable us to be bus
activatable.
https://bugzilla.gnome.org/show_bug.cgi?id=741666
If the autorestart hint is set, the process is forcefully killed and
restarted everytime it disconnects from XSMP, which break replacing the wm
and breaks alt-f2 r. If instead the hint is not set, the process
is monitored via SIGCHLD and only restarted when it dies by a signal.
https://bugzilla.gnome.org/show_bug.cgi?id=648384
