Option to create dummy sensor

Address feature request #10. When the makeDummySensor config setting is true, a contact sensor will be created alongside each Volumio zone. The sensor will be open while music is playing and closed while paused or stopped. This allows you to create automations based on player state.

Webradio STOP instead of PAUSE

Volumio doesn't handle the PAUSE command for webradio sources very well. This change intercepts a PAUSE and sends a STOP instead.

Fix Volume Adjustment

Fixed a few things. Volume clamp util being an important one. Added more verbose debug logging.

Now with Web Sockets!

Merge pull request #2 from mcclurec/socket-api

Reimplement with web socket instead of REST api

Fix Pause/Play

setTargetMediaState now uses explicit passed state instead of toggle API

Up and running

Basic functionality. Pause/play works. Volume and Mute are included, but ineffective in Homekit