IPv6 integration to *BSD

Put in kernel IPv6 code, disabled by default
Stabilize, and enable by default

Make basic applications (like telnet) IPv6-aware
in most cases, gethostby{name,addr} -> get{name,addr}info transition
it helped cleaning up many of the tools

Make thirdparty software IPv6-aware
make a patch and send to the original author (for instance, of python)
discuss with the original author about how the IPv6 support should be integrated
adjust patches
now IPv6 integrated!