Replication controller

Development branch to support k8s replication controller.

In progress, unstable. Use at your own risk.
@ConnorDoyle What's the right way to send the message "kill this pod that I launched but has not yet reported RUNNING back to master yet"? 

I think the code here is doing the right thing, and it's the code in the executor that needs to account for various pod states when it receives the KILL signal, right?