title: Graphviz dot not work on OS X Yosemite
body: <p>I have a dot file that I want to convert to a <code>ps</code> or <code>png</code>. 
  Graphviz is installed with <code>brew</code> on OS X Yosemite. 
  However, <code>dot</code> fails to convert with the following output:</p>
  
  <pre><code>Borkdude@macbookair-michiel /tmp $ dot -Tps foo.dot -o foo.ps
  Format: "ps" not recognized. Use one of:
  </code></pre>
  
  <p>Where to look next?</p>