RESTClient is an abstraction on top of arbitrary HTTP endpoints that
follow the Kubernetes API conventions. Refactored RESTClientFor so that
assumptions that are Kube specific happen outside of that method (so
others can reuse the RESTClient). Added more validation to client.New
to ensure clients give good input. Exposed APIVersion on RESTClient
as a method so that wrapper code (code that adds typed / structured
methods over rest endpoints like client.Client) can more easily make
decisions about what APIVersion it is running under.
* Allows consumers to provide their own transports for common cases.
* Supports KUBE_API_VERSION on test cases for controlling which
api version they test against
* Provides a common flag registration method for CLIs that need
to connect to an API server (to avoid duplicating flags)
* Ensures errors are properly returned by the server
* Add a Context field to client.Config
