title: Ignore everything in a directory except one subfolder
body: <p>I have a directory <code>~/x7/music/sfx</code>.<br>
  There are some files and folders in the root of <code>~/x7/music</code>.<br>
  I need to sync only the <code>sfx</code> folder and ignore anything else in <code>music</code>.  </p>
  
  <p>I've tried many variants, but all of them was wrong.</p>
  
  <pre class="lang-sh prettyprint-override"><code>ignore = Name music/*
  ignorenot = Regex music/sfx/.* (OR just *)
  </code></pre>
  
  <p>does not work.</p>
  
  <p>I was expecting to use something like</p>
  
  <pre class="lang-sh prettyprint-override"><code>ignore = Name music/*^/
  </code></pre>