raw DNS interface to the Docker API

 "rawdns" is a DNS forwarder that allows for DNS requests to return the IP
 addresses of Docker containers directly.
 .
 For example, if one has a container named "app", then a request for
 "app.docker" would return the IP address of that container. Likewise, if the
 "app" container has a linked database container whose alias name is "db", then
 a request for "db.app.docker" would return the IP address of the linked
 database container.