Proposal: Separate desired and current states

Speculative change for some items from #1200:

* Metadata that applies to resources is split from APIMetadata on non-resource API objects
* Metadata is a sub field of objects
* Labels are on Metadata
* Pod current and desired state is split
* Name is used for pods instead of ID (UID is part of metadata, Name is part of resource) for idempotent creation #148 and #1216 
* PodTemplate is a Metadata carrying object as per #170
 * If replicationController gave way to a generic "replicator", then pod template could be both a nested struct and a real resource.
* A ScheduledPod and ScheduledPodList is what the kubelet sees as per #860
* Non-schema'd k/v values on Metadata as `Config` (better names welcome) as per #1201

Not changed yet:

* ReplicationControllers
* Services

Only look at the second commit, the first is just to get a nice diff from v1beta1.
It seems impossible to present status from three containers in a single field without losing something. And anyway, if your policy is NeverRestart, and one of your containers has exited, who's to say that's an error? If that was an error state, maybe NeverRestart isn't the right policy-- you need something that fails the whole pod if one of the containers exits.