Add link to documentation.
Implement android device token retrieving logic.
Merge branch 'master' of github.com:ascariandrea/afw
Add gcm intent service and broadcast receiver to handle push notification.
Add default permissions for google plus login, change support-v4 and google-play-services libraries versions for android-L compatibility.
Fix google plays services, refactor for google sign up logic.
Add method missing in the rebase.