Propagate/notify device state changes to UrfKillswitch objects

I noticed killswitch changes to WLAN on my system did not get properly updated -- one I toggled WLAN to blocked with the killswitch input (Fn+F5 here), any new presses of Fn+F5 would still trigger setting the state to blocked.

I tracked it down to the UrfKillswitch object not updating its states because it was never getting the changed signal from UrfDevice.