Revised version of the basic API

draft-ietf-ipngwg-rfc2553bis-xx
00 is available, 01 will soon be out.

major changes
clarification on bind ordering, etc for more portability.
new socket option: IPV6_ONLY to specify an AF_INET6 socket not to accept IPv4 packets.
due to variation of existing code base, we can't expect much from the new version, though.
scoped address support
getaddrinfo() will accept the "% notation".