code: function registerFont(folder) {
      var data = fs.readFileSync(folder + "/font.json", {encoding: "utf8"});
      var fontArray = JSON.parse(data);
      for (var i = 0, len = fontArray.length; i < len; i++) {
          var font = fontArray[i];
          font.path = folder;
          mdjson.Font.registerFont(font);
      }
  }
docs: Register a font
  @param {string} folder