title: FullCalendar header buttons missing
body: <p>I am using <a href="http://arshaw.com/fullcalendar/">fullCalendar</a> as below
  and have defined header section, everything works ok except header where it's only showing title but
  next, prev, month view etc buttons are missing</p>
  
  <p>if I remove word 'title' it removes title so it seems to be doing something but just not showing buttons, any ideas why? am I missing something?
  my code looks like below:</p>
  
  <pre><code>jQuery('#calendar').fullCalendar({
      header: {
          left: 'prev,next today',
          center: 'title',
          right: 'month,agendaWeek,agendaDay'
      },
      eventSources:
      [{
          url: url,
          color: '#ffdce5',
          textColor: 'black' 
      }]
  
  })
  </code></pre>