Ability to undo

[dkniffin]

This should be relatively easy. I think redux has something built in for stepping back one state. Things might be complicated by the fact that we have multiple events dispatched from one event. We don't want to undo to those intermediate states. For example, when we discard from hand, we send one event to remove from hand, and another to add to graveyard. We don't want to just remove from graveyard, and not put it back in hand.