The PrintingVisitor should print the RootNode in case nothing changed #30
Description
The PrintingVisitor only prints nodes, that have changed in some way and do not contain any children. This way the output will not be flooded with nodes that have implicit changes, because one of their children has changed. While this is pretty neat, I think it makes sense to print the root node, in case it didn't change and doesn't contain any children. I could be wrong, but right now this seems reasonable to me.