docs: function BitmapFontLoader(url, crossorigin)
  {
      /*
       * i use texture packer to load the assets..
       * http://www.codeandweb.com/texturepacker
       * make sure to set the format as 'JSON'
       */
      EventTarget.call(this);
  
      /**
       * The url of the bitmap font data
       *
       * @property url
       * @type String
       */
      this.url = url;
  
      /**
       * Whether the requests should be treated as cross origin
       *
       * @property crossorigin
       * @type Boolean
       */
      this.crossorigin = crossorigin;
  
      /**
       * [read-only] The base url of the bitmap font data
       *
       * @property baseUrl
       * @type String
       * @readOnly
       */
      this.baseUrl = url.replace(/[^\/]*$/, '');
  
      /**
       * [read-only] The texture of the bitmap font
       *
       * @property baseUrl
       * @type String
       */
      this.texture = null;
  }