TrackingPlayer plays reasonably, but still makes mistakes/crashes
Add debug for possiblility errors.

Also no longer gives clue warning against discarding a card that
will be played next anyway
Fix sense of check of pending plays when giving discard clue
Don't play card someone else is going to play
Don't ignore results of MakeDiscardClue
Choose which clue to give more intelligently
Improve clue selection logic
Fix log message