aerogear-push-ios-demo app does not provide feedback on successful registerWithClientInfo

aerogear-push-ios-demo app logs error on failed registerWithClientInfo, but fails to give feedback on success on https://github.com/aerogear/aerogear-push-ios-demo/blob/master/PushTest/AGAppDelegate.m#L74

A log (or another feedback) might be useful for developers.

e.g. NSLog(@"Device successfully registered to PushEE server.");