Fix feedback

Hi there, I spotted a problem with the feedback module - it wasn't reading from the TLS connection.

This should fix the issue, but there's still one thing I'm not sure about  - the endian-ness of the device token itself. Apple's [documentation is a little unclear](https://developer.apple.com/library/ios/documentation/NetworkingInternet/Conceptual/RemoteNotificationsPG/Chapters/CommunicatingWIthAPS.html#//apple_ref/doc/uid/TP40008194-CH101-SW3), but it looks like the "exception proves the rule" and it should be little-endian to me.

 I'll update the PR when I've verified one way or another.