This switches from gsound to libfeedback to provide haptic feedback. Current downsides are
libfeedback does not care about the sound theme so we get the default ringtone (feedbackd#17)
- libfeedback is not as precise as gsound atm when ending feedback (that does not matter much with the current ringtone though) (feedbackd#10)
I've left the notification part in this MR as well for the moment.
Closes: #130 (closed)