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.)
okay, so `01234` works correctly if no `1234` exists?

then i would say just cast $relPath to string at the head of this method. `$relPath = (string) $relPath;` to avoid accidents. can you ammend like this?

about testing, the best place would be to add something to phpcr-api-tests. this is a functional test suite and would make sure the fix works with all phpcr implementation. having some tests in there with nodenames and string properties with leading 0 would be a good thing to know we don't mess up.