code: function reverseAnimation(name) {
           if (typeof name !== "undefined" && typeof this.anim[name] !== "undefined") {
             this.anim[name].frames.reverse();
           } else {
             this.anim[this.current.name].frames.reverse();
           }
  
           return this;
         }
docs: reverse the given or current animation if none is specified
  @name reverseAnimation
  @memberOf me.Sprite.prototype
  @function
  @param {String} [name] animation id
  @return {me.Sprite} Reference to this object for method chaining
  @see me.Sprite#animationspeed