Fixes #209
Updated README
Fixed a bug in scaling down channels where the worker itself wasn't disposing but the underlying channel was instead.  Fixes #210
Added a check to see if the AppleNotification's DeviceToken is empty or null and raise an exception if it is.
Added a check to see if AppleNotification's DeviceToken is null or empty, and if so, raise an exception.  Closes #211
Added changes again from bc57cf4 that somehow reversed
Merge branch 'master' of git://github.com/Redth/PushSharp

Conflicts:
	PushSharp.Apple/FeedbackService.cs