[GAE Server] Refactored code of activity notifications
[GAE Server] Setting GCM and APNS related values depending on current server
[GAE Server] Protected push notification url
Merge branch 'feature/push-notifications' of github.com:usersource/anno into feature/push-notifications
[GAE Server] Calling PushTaskQueue only when atleast one device id present
[GAE Server] Changed push notification message type for iOS
Merge branch 'feature/push-notifications' of github.com:usersource/anno into feature/push-notifications
[GAE Server] Renamed activity notifications
Merge branch 'feature/push-notifications' of github.com:usersource/anno into feature/push-notifications
[GAE Server] Changed data format for push notification
[GAE Server] Updated GAE project structure