Ignore resources that have 0 pods

[cnwaldron]

We currently use the flag to only scan the current revision however, we get a lot of false scans for old deployments/jobs/etc that have 0 pods. Ideally, I'd just have everyone clean up their resources but that's a slow painful process. :)
It would be really helpful if there was a way to only scan the resources that actually have a pod running to get a more accurate overview of the cluster.