title: ZF2 Hostname Routing with found value as default
body: <p>I want to create a whitelabel-ready site and want to use the hostname routing for that. 
  I created a parent-route for all other routes, which just stores the found hostname in a variable called "whitelabel"</p>
  
  <p>The created array:</p>
  
  <pre><code>&lt;?php
  $route = array(
  'type' =&gt; 'Hostname',
      'options' =&gt; array(
      'route' =&gt; ':whitelabel',
      'defaults' =&gt; array(
          '__NAMESPACE__' =&gt; 'Application\Controller',
          'controller' =&gt; 'Index',
          'action' =&gt; 'index',
      ),
  ),
  );
  ?&gt;
  </code></pre>
  
  <p>Right now, whenever I call the url helper in views it is unable to find a value for 'whitelabel'. How can I store the found value as default value for the url helper?</p>