THe music module expects an event to be sent on subscription to the
client to set up the initial state. This ensures an event is sent when
in MPRIS mode when no player is initially found.
Resolves#25.
Completely refactors the MPD module to be the 'music' module. This now supports both MPD and MPRIS with the same UI for both.
BREAKING CHANGE: The `mpd` module has been renamed to `music`. You will need to update the `type` value in your config and add `player_type` to continue using MPD. You will also need to update your styles.
