Created ControlChangeNotifier, which is designed to tell the UI when a designated control signal has changed.
Merged in from development branch
Changed some names in the ControlChangeNotifier system.
ControlChangeNotifier can now accept multiple subscribers. ControlChangeSubscriber can now be unsubscribed. ControlChangeSubscribers can now be added without specifying a name.
Merge pull request #171 from TonicAudio/MP-ControlChangeNotifier

Mp control change notifier