Add @InterfaceAudience annotations and move ValidationContextImpl to its own file.
add @InterfaceAudience annotations
add more @InterfaceAudience annotations
add more @InterfaceAudience annotations and make a few methods non-public that don't need to be public.
Add ability to set http client factory on the manager and have it used in pull replications.  Update one of the tests to use this style of using a custom http client factory.