Attempt at mediator implementation for handling `before`/`after` controller requests.

gistfile1.php

<?php
$controller = $container->create($request->controller);
$mediator = $container->create('BeforeMediator');

$controller->registerMediator($mediator);
$controller->triggerActions();

$response = $container->create('Response');
$controller->{'action' . $request->action}($request, $response);

class BeforeMediator {
  /* snip */
  public function notify($action) {
    foreach ($this->registrants as $r) {
      $r->$action();
    }
  }
}
class Controller {
  /* snip */
  public function triggerActions() {
    $this->mediator->notify('beforeRequest')
  }
}
?>