title: Slim PHP Hook for after route, before render
body: <p>Currently I'm trying to implement this behavior:</p>
  
  <ol>
  <li>I make several routers</li>
  <li>Inside a router, I change an environment variable</li>
  <li>That environment variable is accessible on <code>before.dispatch</code></li>
  </ol>
  
  <p>Basically, I want to be able to do this:</p>
  
  <pre><code>$app-&gt;get('(/)', function() use ($app, $env) {
      $env['title'] = 'My page title';
      $app-&gt;render('index.tpl', array(
          'test' =&gt; 'Test!!!',
      ));
  });
  </code></pre>
  
  <p>While I also have this: </p>
  
  <pre><code>$app-&gt;hook('slim.before.dispatch', function () use ($app, $env) {
      $app-&gt;view()-&gt;appendData(array(
          'env' =&gt; $env
      ));
      if (!isset($env['partial']) || $env['partial'] != true)
          $app-&gt;render('header.tpl');
  });
  </code></pre>
  
  <p>Problem is, the $env['title'] is only available in <code>index.tpl</code>, and not <code>header.tpl</code>, I'm assuming because in <code>before.dispatch</code>, I don't apply the route yet.</p>
  
  <p>How can I achieve this behavior without having to <code>applyHook()</code> at every route I need to change header template variables for?</p>
  
  <p>Thank you!</p>