Multiple variations

[dkniffin]

Right now, we only support one rule set, which is a combination of this and this. It'd be nice to let the user choose which rules to play with.

From the user perspective, I can see this done in a couple ways. We could have a drop down that the user chooses a ruleset, or we could have some checkboxes to enable/disable different rules. Or both, maybe.

From a technical perspective, we'll need to save the user's choice somewhere (probably in the state), and read from it wherever we need to.