Update to Google Oauth 2.0 login 

per the instructions at:
  https://developers.google.com/+/api/auth-migration#userinfo

This has not been extensively tested, but has been lightly tested in our application.

I believe this is done.  Please also review the change to JsonHelper!
Just to be sure: the JSON parser will create two nodes for attribute: ```n1.n2```, the parent node ```n1``` and the child node ```n2```.

So that's why you follow the tree of nodes, don't you? I searched a Jackson option for that but couldn't find one.