- playAudioFile() makes it possible to play a WAV file
to either the caller or the mumble channel
- menu skeleton has DTMF handling and is ready for
adding '*n' functions (like *5 = mute).
This causes the user to be self_mute and self_deaf when there
is no SIP call active. Users in other Mumble groups can then
see whether the user is active without moving to same group.
Note: this needs the updated mumlib with the self_mute and self_deaf
methods