title: Update an event by dropping an external event
body: <p>fullcalendar 1.4.7 allow adding new events by dropping them onto the calendar from an external list of events.
  I would like to update the title of an existing event by dropping another event from the same list. How i can do that.
  I wrote this function (below) and i call it from the "bindSegHandlers" function of fullcalendar.js but it doesn't work, a new event is created. </p>
  
  <pre><code> function droppableEvent(event, eventElement) {
    eventElement.droppable({
     accept: '.myevent',
     tolerance: 'pointer',
     activeClass: 'ui-state-hover',
     hoverClass: 'ui-state-active',
     drop: function(ev, ui) {
      alert('call dropped');
     }
    });
   }
  </code></pre>
  
  <p>Can you help me?</p>
  
  <p>thanks</p>