Implement inet_ntop on windows less than vista where it does not exist.

Fixes #50.
Initialize sa_family and zero the remaining members in sockaddrs
Indentation and coding style
Handle bogus address families in our inet_ntop implementation
_WIN32_WINNT < 0x0600, since 0x0600 is Vista
Merge pull request #59 from p-push/inet-ntop-windows

Inet ntop implementation for windows that do not have it (< vista)