static function load($filename)
	{
		if (isset(self::$stack[$filename])) return self::$stack[$filename];
		$path = self::get("apppath") . "config" . DS . $filename;
		if (!file_exists($path)) throw new \Exception("Config file '$filename' not found'");
		$config_data = include($path);
		self::set($filename, $config_data);
		return $config_data;
	}