title: Revealjs video not playing
body: <p>I juste resume a project using Reveal.js. I have added and edited a few section successfully and I wanted to add a simple video so I added this:</p>
  
  <pre><code>&lt;section&gt; 
  &lt;video poster="img/video_poster.jpg" controls&gt; &lt;source data-src="http://clips.vorwaerts-gmbh.de/big_buck_bunny.mp4" type="video/mp4"&gt; &lt;/video&gt; 
  &lt;/section&gt;
  </code></pre>
  
  <p>I can see the video, the poster and I can see the controls, I am just not able to press the PLAY button on the video. I can press on the other controls like "Mute" and "Full Screen", so I imagine is not a problem of z-index. The section is quite simple as you can see, it doesn't have anything apart from the video. Any idea?</p>
  
  <p>I have also tried to remove all my code and create a test page just with the basic code used to initialise Revealjs and it still doesn't work.</p>
  
  <p>Thanks</p>