Only update _underscore to 1.6.0, because of the templating stuff

underscore 1.7.0 changes _.template() method to return a function.
When upgrading, we need to change

From
  _.template('str', date)

To
 var tmpl = _.template('str');
 tmpl(data);

This needs to change all places covered by

`git grep -n  "_\.template"`