[PA3] Add two-player mode

[Sencudra]

No need to go overboard here. Maybe just a button for each user that can be used to claim they see a Set on the board, then that player has a certain (fairly short) amount of time to actually choose the Set or the other person gets a turn (with twice as much time to find a Set)? Most Sets found wins. Hitting Deal 3 More Cards on one user’s side might give the other person a medium amount of time to find a Set without penalty if they can’t? Up to you. You’ll probably need Timer (as mentioned in last week’s extra credit) to do this one.