Improve terminal output. Fix bug.

Player class names are outputted instead of "player0" and "player1".
Also, when tournament concludes, the author names and class names
of the top three scorers are printed.

Fixed bug in PDDriver, where classes that did not implement the
PDPlayer interface were removed from playerList.

Added another test class, "BrokenPlayer2", which does not implement
the PDPlayer interface, and thus gets removed from the playerList.

This version should be adequate for classroom use.