When constructing an f-resilient uniform strategy, the read quorums were
being used for the write quorums. I added a unit test that fails because
of this bug and then fixed the bug to make the test pass.
Thanks so much @samueleresca for finding this bug!
Some of the code was nasty. I cleaned it up a bit. I also started moving
tests into a tests/ directory. You can run python -m unittest to run
them. I still need to add more tests to make sure things are working as
expected.
