code: function removeEvent (date, index) {
    date = this.toDate(date);
    if (!date) {
      return false;
    }
    var info = getDayInfo(this.dayInfo, date);
    if (!info) {
      return false;
    }
    var events = info.events;
    if (arguments.length === 1) {
      events.splice(0, events.length);
      return true;
    }
    if (events.length <= index) {
      return false;
    }
    events.splice(index,1);
    return true;
  }
docs: イベントを削除
  @method removeEvent
  @param  {DATE} date
  @param  {Number}      index    省略時にすべてのイベント削除
  @return {Boolean}     removed