Node 0.11.x support

With these changes, node_mdns builds and runs under Node 0.11.14 and nan 1.3 although I cannot say with certainty as amount of testing it received with these changes is too little.
Yes, the idea is to use `NanNew<Uint32>()`. See the cryptic tests for examples of intent.
https://github.com/rvagg/nan/blob/master/test/cpp/news.cpp#L39-47
https://github.com/rvagg/nan/blob/master/test/js/news-test.js#L45-46