Many changes and debugs

Patch Pile init; Use dummy top card for empty piles; Patch 4-of-a-kind
detection; Add played-onto-empty-pile detection; Patch facedown.flip();
Create Faceup and Hand play() methods; Add lots of UI messages for game
events; Combine turn methods and create Player.turn(); Detect win
conditions; Add playing-multiple-cards functionality; Add to UI by
creating choose_x functions for playing multiple cards