podex: initial import

podex is a command line tool to bootstrap a kubernetes container manifests from docker image metadata.

Manifests can then be edited by a human to match deployment needs.

Example usage:
```
$ docker pull google/nodejs-hello
$ podex -yaml google/nodejs-hello > google/nodejs-hello/pod.yaml
$ podex -json google/nodejs-hello > google/nodejs-hello/pod.json
```

The `podex/manifests` subdirectory could also be used to host example pods for popular docker images.
The format spec is `[REGISTRYHOST/][USERNAME/]NAME[:TAG]`, added a comment.

The `NAME` doesn't allow `/`, so the last thing after the `/` should be the image name always.