Enable DNS for services

Open issues as of 11/15

Needs e2e testing

Question: Can services exist above "default"?  I.e. do we need to search (domain) and (ns).(domain) or just (ns).(domain) ?

Should default.(domain) be in everyone's search list?

TODO: plumb DNS to minion's resolv.conf for use from host

TODO: fix portals for UDP from host (works from a container)
 - source address is wrong on response from host:
   OUTPUT -> -A KUBE-PROXY-LOCAL -d 10.0.0.10/32 -p udp -m comment --comment skydns -m udp --dport 53 -j DNAT --to-destination 10.240.239.33:41504

TODO: Need a specific version tag on the skydns, kube2sky, and etcd containers.

Oh. I see from the kubelet code that this option is about giving the pod access to cluster DNS, not about not publishing the pod. Maybe the name can be improved. Doubly unsure about the use case now, though.