Proposal for v1beta3 API

* Separate metadata from objects
* Treat lists differently from resources
* Add UID and Annotations on Metadata
* Introduce BoundPod(s) as distinct from Pod to represent pods
  scheduled onto a host
* Use "spec" instead of "state" and "status" instead of "currentState"
  * Identify current status of objects consistently
* Rename Minion -> Node
* Remove ContainerManifest
* Add api-conventions.md document