Many many Sonos binding fixes and improvements

 - Fix issues #433, #476 and #608
 - Prepare support for all types of Sonos HW
 - Improve network scanning 
 - Replace pollingthread by selective polling based on Quartz Jobs
 - Make binding a "good" openHAB citizen (new base abstract class)
 - Changed item binding syntax (removed <direction>)
 - Improved Volume control
 - Improved PlayList and Radio URI management