code: function(beginValue, finishValue, setter) {
                  if (arguments.length == 1) {
                      var opt = arguments[0];
                      this.beginValue = opt.beginValue;
                      this.finishValue = opt.finishValue;
                      this.setter = opt.setter;
                  } else {
                      this.beginValue = beginValue;
                      this.finishValue = finishValue;
                      this.setter = setter;
                  }
              }
docs: @constructor
  @for kity.Animator
  @catalog animate
  
  @grammar new kity.Animator(beginValue, finishValue, setter)
  @grammar new kity.Animator(option)
  
  @param  {any}      beginValue|opt.beginValue
  动画的起始值，允许的类型有数字、数组、字面量、kity.Point、kity.Vector、kity.Box、kity.Matrix
  
  @param  {any}      finishValue|opt.beginValue
  动画的结束值，类型应于起始值相同
  
  @param  {Function} setter|opt.setter
  值的使用函数，接受三个参数: function(target, value, timeline)
  target   {object}        动画的目标
  value    {any}           动画的当前值
  timeline {kity.Timeline} 动画当前的时间线对象