hasMoved = function (oldChild) {
            var oldChildInNewTree = newNodeMap[oldChild.tagID];

            return oldChild.children && oldChildInNewTree && getParentID(oldChild) !== getParentID(oldChildInNewTree);
        }
Looks to see if the element in the old tree has moved by checking its
current and former parents.

@return {boolean} true if the element has moved