Distributed tests were failing every now and then because the test
plugin didn't implement retry's and the test server wasn't always
starting up fast enough. I fixed this by refactoring the tests to use
the real TLS plugin, which has retry logic. This required some mangling
of the configuration options, which should serve as a good reference as
well.
This introduces the notion of a DistributedQueryHandler that uses a "provider" to read/write requests and results to and from the master. The full flow is exercised via integration tests, and unit tests for each component.
It is intended to foster discussion around this client side interface, as well as provide a base to build from.
