title: Fullcalendar dayRender: Cannot read property 'format' of undefined
body: <p>I am working with Fullcalendar. I create events now by dragging and dropping. I want to do it with a double click on a day. I am trying to use the dayRender function but "event.start.format()" is undefined.</p>
  
  <pre><code>dayRender: function(event, element) {
              element.bind('dblclick', function(event,element) {  
                      var title = prompt('Event Title:', event.title, { buttons: { Ok: true, Cancel: false} });
                        if (title){
                          console.log(event);
                            event.title = title;
                            var start = event.start.format("YYYY-MM-DD[T]HH:MM:SS");
                            $.ajax({
                                  url: '{!!URL::route("saveCalendarEvent")!!}',
                                  data: 'type=new&amp;title='+title+'&amp;startdate='+start+'&amp;zone='+zone,
                                  type: 'POST',
                                  dataType: 'json',
                                  success: function(response){    
                                  event.id = response.eventid;
                                  $('#calendar').fullCalendar('updateEvent',event);
                                  },
                                  error: function(e){
                                      alert('Error processing your request: '+e.responseText);
                                  }
                              });
                        }
  
              });
          }
  </code></pre>
  
  <p>The error:</p>
  
  <blockquote>
    <p>Uncaught TypeError: Cannot read property 'format' of undefined</p>
  </blockquote>