@Override
    public T set(final int index, final T element) {
        return list.set(index, element);
    }
Creates new grouped list
@param list container to be used by this group list.
            WARNING: GroupList assumes to be the sole manipulator of this list. Parallel editing in other places leads to undefined behaviour
@param defaultGroup default group to assign to new/first element when list is empty
main/src/main/java/cgeo/geocaching/utils/GroupedList.java