These are the code adjustments required for having a functional GCM class for Android Push notifications.

It is not a complete rewrite of the class, so it does not yet contain all the new features (multicast messaging etc). It is more of an adjustment of the C2DM class, which contains the modifications on the headers and the message format (which is now JSON) and the removal of the functions related to the Google Authentication Token for servers.

The current changes comply to the file & path structure of Lunr-0.2. Next step after this review is to port those changes back to Lunr-0.1, so that the projects which use this functionality continue to work.

Tested with Piet's Android device.