Create a new Menu instance.
@memberof Menu
@constructs
@param {Object} [props] - A dictionary of properties to initialize a Menu with.
@static
function create(props) {
    var menu = Object.create(this);

    _domWidget2.default.create.call(menu);

    Object.assign(menu, Menu.defaults, props);

    menu.createOptions();

    menu.element.addEventListener('change', function (e) {
      menu.__value = e.target.value;
      menu.output();

      if (menu.onvaluechange !== null) {
        menu.onvaluechange(menu.value);
      }
    });

    return menu;
  }