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.
Ok, here is one example. A pod has 3 containers with RestartPolicyNever configed. Container A is terminated with exit code -1, Container B, C are still running happily. In today's system, we reset the PodStatus back to PodWaiting, which is obviously wrong to me. But which other state Pod should be? It is a permanent error, but shouldn't put the entire pod to PodTerminated. 

Without Error state at pod level, I am ok to leave pod at PodRunning state with error state for Container itself.