title: Fullcalendar - Not able to display day names in Month view
body: <p>I'm using full calendar 3.4 and trying to show day names in the month view, but nothing seems to work. 
  Works fine in Week view though.</p>
  
  <p><a href="https://i.stack.imgur.com/6QKR6.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/6QKR6.png" alt="enter image description here"></a></p>
  
  <p>Tried multiple different things and here is my configuration:</p>
  
  <pre><code>$('#calendar').fullCalendar({
  
          defaultView: 'month',
          weekNumbers: true,
          selectable: true,
          selectHelper: true,
          selectOverlap: false,
          timeFormat: 'H:mm',
          firstDay: 1,
          views: {
              month: {
                columnHeaderFormat: 'ddd'
          }},
  
  
          header: {
              right: 'prev,next today',
              left: 'title',
              center: 'month,agendaWeek,agendaDay'
          } });
  </code></pre>
  
  <p>Any ideas how I can make it to work?</p>