Improve update demo, support rolling template update

This improves the update demo pretty dramatically.

* Makes the demo more visual, fixes some HTML layout
* Make naming of objects in `kubecfg run <image> <replicas> <controller>` more obvious
* Run update demo without pushing/creating new containers in docker hub (slow)
* Improve e2e tests to actually do the rolling update
ReplicationController should never, ever validate whether the pods it controls are out of spec or not. That would radically reduce the flexibility of replication controller and push rolling update functionality into it. Let's not go there. It's a composable building block.