title: Template changes not showing with Sulu
body: <p>When I bootstrap a new project using the latest version and documentation, and then add some properties to the <code>homepage.xml</code> or render some text in the <code>homepage.html.twig</code> nothing changes.</p>
  
  <p>In <code>homepage.xml</code> I added this</p>
  
  <pre><code>&lt;property name="header" type="media_selection"&gt;
       &lt;meta&gt;
           &lt;title lang="en"&gt;Header&lt;/title&gt;
       &lt;/meta&gt;
  &lt;/property&gt;
  </code></pre>
  
  <p>directly below the <code>article</code> property, and when I go to the admin page, the <code>header</code> doesn't show up. </p>
  
  <p>Same thing with small changes to the twig file. When I dump the content var there, nothing shows up.</p>
  
  <p>Any ideas on what the problem might be?</p>