Set the default TTL of hostnames resolved by dnsmasqd to 0 so the clients (in theory) won't
cache them.

Added code to bounce avahi-daemon to ifplugd.action to (un-)propagate DNSes whenever a
gateway comes up or goes down.

Signed-off-by: The Doctor <drwho@virtadpt.net>
Merge branch 'master' of https://github.com/Byzantium/Byzantium