Add container hashing to the container name, and restart containers on changes.

Closes https://github.com/GoogleCloudPlatform/kubernetes/issues/677
The hash is close to the intended podInstanceID from https://github.com/GoogleCloudPlatform/kubernetes/blob/master/docs/identifiers.md in 8-3.  Should we just hash the entire pod and then kill containers that don't match it?  Or, pod instance id could be an extra field and complement the hash?  The pod changed, but we don't have anything to track new container x is part of new pod version y.  I guess that can be resource version.