title: Passing PHP global variables via Twig/Timber
body: <p>According to <a href="https://stackoverflow.com/a/19554524/6450661">https://stackoverflow.com/a/19554524/6450661</a>, standard Twig provides a method via <code>{{ app.request }}</code> that I can use to pass $_GET, $_POST, $_SESSION, etc. variables.</p>
  
  <p>Using Timber, is there a similar method? I can use Timber\URLHelper's get_params() method to access $_GET variables, but that's about all I can seem to find.</p>