code: function moveToTop(child) {
           var childIndex = this.getChildIndex(child);
  
           if (childIndex > 0) {
             // note : we use an inverted loop
             this.children.splice(0, 0, this.children.splice(childIndex, 1)[0]); // increment our child z value based on the previous child depth
  
             child.pos.z = this.children[1].pos.z + 1;
           }
         }
docs: Move the specified child to the top(z depth).
  @name moveToTop
  @memberOf me.Container.prototype
  @function
  @param {me.Renderable} child