Merges master into branch 1061592. adds checkbox, stores pref on server and local

@Rik r? This is the first part of a two steps. I had to split this into two, to clean up the other pull request that was merged and then backed out and, to create smaller easier/faster to review pull requests.

This pull requests:

1) Adds the checkbox to enable or disable new comment notifications
2) Send and stored that value on the server in user.settings
3) Updates the local user data with the same preference also stored in the user.settings array
With the change you suggested we loose the User object. Should I just do 

    ...
    var user;

    User.get_user().then(function(user) {
        user = user;
       return SumoDB.update_preference(user, settings);
    }).then(function(setting) {
      // …
    });

ore leave as is?