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.
I merged Strategy and ExplicitStrategy for now. I also pruned zero
probability quorums from the strategies. The load plots are cool. I want
to plot capacity plots now, though it's a little tricky.
