title: In fullCalendar change slotDuration without page reloading
body: <p>Using fullcalendar I need without page reloading to change <code>slotDuration</code> parameter depending on other conditions:</p>
  
  <p>I do in one case</p>
  
  <pre><code>$('#calendar').fullCalendar('option', 'slotDuration', '00:15:00');
  </code></pre>
  
  <p>and in other case</p>
  
  <pre><code>$('#calendar').fullCalendar('option', 'slotDuration', '00:30:00');
  </code></pre>
  
  <p>But looks like it does not work, as I always see fullcalendar with <code>slotDuration=30</code> (2 slots) minutes, as it was called when initialized.</p>
  
  <p>If there is a way for this?</p>