Disable XInput on cinnamon startup (for 3.8 compat)
This has no effect on < 1.14 clutter
Explain change
Merge remote-tracking branch 'mtwebster/clutter-compat'
Merge remote-tracking branch 'mtwebster/gnome-3.8-compat'

Conflicts:
    files/usr/share/cinnamon/applets/power@cinnamon.org/applet.js
    files/usr/share/cinnamon/applets/sound@cinnamon.org/applet.js
[Connector] use connectSignal/disconnectSignal if available