Treat numeric node names with leading zeroes as different from those wit...

...hout. -- #234

(Note that I looked into adding a unit test for this but couldn't find a way to easily test this portion of `Node::addNode` without adding a lot of extra code.)
could this not lead to a problem when i add a node named `3` and the same node named `"3"`? are we making sure that nodenames are always strings?