Some cleanup and enhancements:
- The service for the group is now called Sonos, e.g. Living Room Sonos;
- The optional service for the zone is now called Speakers, e.g. Living Room Speakers;
- The config.json setting to enable the optional Speakers service is:
"speakers": true; - Added support for Bass, Treble, and Loudness (issue #7) to the optional Speakers service;
- Adjusted README and log messages.