title: twig filter multiple parameters
body: <p>I'm trying to create a specific twig filter that can handle 2 parameters. </p>
  
  <pre><code>$documentURL = new Twig_SimpleFilter('documentURL', function($DocumentId, $UserId){
  
      $URL = "http://example.example.com/start/".$DocumentId."/".$UserId."/";
  
      return $URL;
  
  });
  </code></pre>
  
  <p>And added the filter to the render: </p>
  
  <pre><code>$twig-&gt;addFilter($documentURL);
  </code></pre>
  
  <p>Now the filter is requested in the template: </p>
  
  <pre><code>{{documentURL(booking.docId, user.id)}}
  </code></pre>
  
  <p>However, i'm getting an error that the function doesn't exist. Quitte strange... Because it does exist and it is included. The same way like my other 15 filters. </p>
  
  <pre><code>Fatal error: Uncaught exception 'Twig_Error_Syntax' with message 'The function "documentURL" does not exist in "profile.html" at line 78'
  </code></pre>
  
  <p>Am I requesting the filter the wrong way? (Probably yes...)</p>