Update jquery.sew.js

added a valuesFactory function to the options
$('textarea[mention_on="true"]').sew({
      values: values,
      elementFactory: elementFactory,
      valuesFactory: function(val, done) {
        // here, you can do a remote call and pass the values to         the callback function 'done' 
        console.log("the value " + val);
        done(values2); 
      }
    });