code: function onEvent(gesture, handler) {
      var gestures = gesture.split(' ');
      Utils.each(gestures, function(gesture) {
        this.element.addEventListener(gesture, handler, false);
        this.eventHandlers.push({ gesture: gesture, handler: handler });
      }, this);
      return this;
    }
docs: bind events to the instance
  @param   {String}      gesture
  @param   {Function}    handler
  @returns {Hammer.Instance}