Added ability to save game stats to DB for TexasPoker and related changes.

- Propagated the saveDBGameStats() method for TexasPoker to update
  TPRound, TPPot, TPPlayerPot, TPPlayerChange, TPPlayerHand tables in the
  DB at the end of a round
- TexasPoker now tracks the start and end times of each round
- Added SQL query Op command to TexasPoker to allow quick debugging of DB
- Improved the way IDs are retrieved after a DB table insertion for all
  games
- Added prefix to logged SQL error messages
- Added colorless toString methods for Card and Hand
- Added ability to store winners in PokerPot