Nathanael Schneider

Done. I forgot to adjust my autoformatting to BSD style, so that's where that came from.

I think this pull request is no longer necessary as 5.0 support is now implemented.

For anyone looking for a workaround - some reflection magic on private methods does allow to refresh the cells - namely calling `CollectionChanged` on the `HierarchicalRows`-Instance. You'll have to adjust...