XML Namespace support.

[tomc974]

Could you please consider adding XML Namespace support to your library?

Contrary to what's written in your README, the underlying sax-js parser seems to support namespaces just fine provided you set the xmlns setting to true. Adding fields for local, prefix, and uri should be easy but I'm not sure how the names should be handled with methods such as childNamed()...

[nfarina]

I think it would be fine to support it as long as the existing API is preserved and it doesn’t complicate the codebase too much. Open to suggestions or PRs!

[tinesoft]

Any update on that issue? It would be a huge improvement of that already-great library