Removed a resolved todo

lib/timeline/component/item/ItemRange.js

@@ -164,7 +164,6 @@ ItemRange.prototype.hide = function() {
  * Reposition the item horizontally
  * @Override
  */
-// TODO: delete the old function
 ItemRange.prototype.repositionX = function() {
   var props = this.props,
       parentWidth = this.parent.width,