Added DHCPv6 minimalist codec (which can be used to produce fake server, tomorrow's exercise).
Added domain search list en-decode.
Added (minimalist dhclient -6 -S) info request sample.
Converted the dhcpv6 cases to be bit more readable.
Refactored mcast join/leave functionality to standalone module, and using it to provide fake DHCPv6 prefix delegation server.