In addition to Getter interface, API Installer now supports a
GetterWithOptions interface that takes an additional options object when
getting a resource. A flag is now returned from rest.ResourceStreamer
that indicates whether the streamed response should be
flushed when written back to the client. This is to support log
streaming.
Dependency chain is now api -> api/rest -> apiserver. Makes the
interfaces much cleaner to read, and cleans up some inconsistenties
that crept in along the way.
