title: fullCalendar multi-day event spans 1 day too short
body: <p>When users add an event to the calendar, they choose start: 2014-09-17 end: 2014-09-18. Simple enough, they expect the event to extend across both the 17th and 18th boxes on the calendar, but it only appears in Sept 17th, making it appear a 1-day event.</p>
  
  <p>In the events manager database 9-17 and 9-18 are entered correctly. I tried changing the nextDayThreshold option of the fullCalendar plugin, but the event still only spans across sept. 17th. I could add a day on the back end, but this causes other issues, I'd rather do it client-side, for display purposes only. </p>
  
  <p>Any way to change this behavior?</p>
  
  <p>thanks.</p>
  
  <pre><code>$("#cal").fullCalendar({
      events:[
          {
              'title':'test2',
              'start':'2014-09-17',
              'end':'2014-09-18'
          }
      ],
      nextDayThreshold: "00:00:00"
  });
  </code></pre>