Blokus [fix]

We like Blokus as an abstract game for 4, but...

The problem: we find there is a small, but significant, first player advantage. Beyond the first player, player order doesn't seem that important, but the first player generally has a bit more space, is a bit faster into the center, etc.

The fix: we restrict the first player's first move to not be a size five piece. That's it. Enjoy!