Set interface with longest prefix in DHCP & DHCPv6 lease

- With nested prefixes reside on different interfaces of single host

  (e.g., in 6to4, 2002::/16 on WAN and 2002:<IPv4>:<subnet>::/64 on LAN),

  current matching mechanism might return the interface with shorter prefix

  length instead of the longer one, if it appears later in the netlink message.

Signed-off-by: Lung-Pin Chang <changlp@cs.nctu.edu.tw>
Fix logic for associating leases with interfaces.

This handles the case that more than one interface contains
the network the lease address is on, but the interfaces have different
prefix lengths. Use the longest prefix length.
Tidy up previous commit.
Add --dns-loop-detect feature.
Check all servers loopiness, when any subset is changed.
Missed update of DHCP lease datastructure.
GetLoopServers Dbus method.
Merge branch 'loop'
Mention name in systemd.
Debian package: use dns-root-data.
RFC4191 route information option.
Fix debian changelog date snafu.
Remove paypal links and icond refs from Debian package.
Bump Debian standards version.
Extend --conf-dir to allow filtering on file suffixes.
Update *.po files for new release.
Revert route-information option in RA. There are problems with some clients.
http://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2014q3/008796.html
DHCPv6 REBIND messages don't need a server-id.
Set DHCPv6 message type when returning "use multicast".
Don't reply to DHCPCONFIRM messages with no addresses in them.