introduction of dnsmasq-utils.

Update debian/rules to provide no_dhcp6 and use_lua build opts.
Log DHCPv6 information request packets.

 be a domain name instead of an IP address. This allows for
 round-robin to multiple servers, in the same way as
 --dhcp-boot.

Counted string DHCP option type printing

TODO
     hostname handling.
     update DHCP6 configs from dns
     parse domain=<domain>,<IPv6 range>
     pretty-print counted string options.
     DECLINE messages
     lease-script fro DHCPv6

stdout and stderr file descriptors open. This can manifest
itself as 100% CPU use. Thanks to Chris Moore for finding
this.

duplicate address code, since we're now searching a temporary hash
which holds only F_HOST records.

Use the packet buffer for hash-buckets, better hash function.