Add an undo button (only usable on certain conditions)

[jasongraph]

Allow a player to undo a turn if:
1. The turn happened at most 30 seconds ago
2. The turn after hasn't yet finished.
3. They didn't just undo a turn (so you can't go 2 turns back)
3. No information was gained since the turn - you can't undo your choice of house card or bids or un-seeing the top card of the wildlings, or change your order placement.

[Tex]

This is probably something that is totally fine when playing in real life, but doing this for online.. Will require a bit of work ([mention]Longwelwind[/mention] ?), for very little gain. So I'm kinda against it, as there are other more important matters IMO.