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
How so?  We are just setting a new image into the template for the first container in the pod.  If kubecfg were a more functional tool (supporting reading templates from disk) it's be more clear what should happen.