Moved more strings to strlib.txt. Other changes.

Renamed msglib.txt to strlib.txt. Moved more display strings to strlib.txt. Added documentation in Blackjack (issue #34). Changed "test" ArrayList in showTopPlayers() to showPlayerRank to be of type Double to combine with showTopWinRate() and showWinRateRank(). Moved methods that require knowledge of the type of game from CardGame back to subclasses. Replaced almost all bot.sendMessage() and bot.sendNotice() calls with showMsg() and informPlayer(). Other small changes.