/**
  * Remove a Core.
  *
  * Remove the Model, View, Controller and Facade
  * instances for the given key.
  *
  * @param string $key MultitonKey of the Core to remove
  * @return void
  */
 public static function removeCore($key)
 {
     if (!self::hasCore($key)) {
         return;
     }
     Model::removeModel($key);
     View::removeView($key);
     Controller::removeController($key);
     self::$instanceMap[$key] = null;
 }