issue 179 upgrading facebook to oauth 2.2 - a

179) check https://developers.facebook.com/docs/apps/upgrading
     warning when asking for read_stream permissions in util_controller.get_api_picture_url_facebook
     koala oauth.url_for_oauth_code returns https://www.facebook.com/dialog/oauth?
     must be changed to https://www.facebook.com/v2.0/dialog/oauth? - ok
     maybe asking for read_stream permission also is a problem - submit for review