Add node status to API object.

@smarterclayton @lavalamp I'm not sure if this is enough to get it work.  Beat me up.  

 @smarterclayton Should I also take care of v1beta3?

Short answer is yes.

See resourceCapacitySpec in https://github.com/GoogleCloudPlatform/kubernetes/blob/master/docs/resources.md. I updated it this week.

Status is more complicated. See Usage Data in the Appendix of resources.md.