Support for New Zealand phone numbers

I have attached a patch to provide support for New Zealand phone numbers.

This has been in production on http://www.signon.org.nz for a few months now and seems to be working well.

It supports mobile, landline and special (0800, 0900) numbers, as well as some other optional ones like Scott Base (but these need to be uncommented explicitly).

I've included a SimpleTest test case for it as well.

Thanks