If the distributed plugin's `writeResults` method can be successfully
called, we must clear the local vector of results so that we're not
constantly growing it over time.
2. Introduce a SQLite-based database plugin
3. Refactor database usage to include local 'fast-calls'
4. Introduce an 'ephemeral' database plugin for testing (like a mock)
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.
