1220 fix XucPhoneEventListener handler registration
Problem:
XucPhoneState and WebRtcAudio used XucPhoneEventListener.addHandler with $rootScope, which is not destroyed on logoung+login which lead to multiple registration (and calls) to callbacks (esp. XucPhoneEventListener.addHandler._onPhoneEvent).
Changes:
- added XucPhoneEventListener.addHandlerUntilLogout
- use it in XucPhoneState and WebRtcAudio
- calling callback from XucPhoneEventListener.addHandler was simplified rootScope.applyAsync
Closes #1220