Multiple listener interfaces; hostname aliasing. .gitignore

This is modifying an open source mdns library to allow aliased mDNS responders, and to listen on multiple interfaces. What this means is that when peerdiscovery_daemon is running, other machines can do:
ping <uuid>.local
and the DNS lookup will resolve and ping will work. This is not strictly necessary but it was used such that the etcd clusters can survive IP address changes and still survive; this may be important within behind the firewall (non aws) deployments.