code: function JumpBy (opts) {
      JumpBy.superclass.constructor.call(this, opts)
  
      this.delta  = util.copy(opts.delta)
      this.height = opts.height
      this.jumps  = opts.jumps
  }
docs: @class
  Moves a cocos.nodes.Node simulating a parabolic jump movement by modifying its position attribute.
  
  @memberOf cocos.actions
  @extends cocos.actions.ActionInterval
  
  @opt {Float} duration Number of seconds to run action for
  @opt {geometry.Point} startPosition Point at which jump starts
  @opt {geometry.Point} delta Number of pixels to jump by
  @opt {Float} height Height of jump
  @opt {Integer} jumps Number of times to repeat