/**
  * Bootstrap the ConfigPress plugin
  * 
  * Register language domain and create a single instance of ConfigPress
  * object
  * 
  * @return void
  * 
  * @access public
  */
 public static function bootstrap()
 {
     if (is_null(self::$_instance)) {
         //register language domain
         load_plugin_textdomain(CONFIGPRESS_KEY, false, __DIR__ . '/lang');
         //create an instance of itself
         self::$_instance = new self();
     }
 }