Implement Tournament Manager

Implement Tournament Manager

New command-line options are added to specify the tourney: -tourneyType
(-tt), -tourneyCycles (-cy), -participants, -syncAfterRound,
-syncAfterCycle, -results, to be saved on a -tourneyFile (-tf), but
otherwise volatile. When a tourneyFile is specified during a match,
a new routine NextTourneyGame is called from NextMatchGame before every
game, to decide the pairing, and unload and redefine the engines, when
needed. The XBoard Match Options dialog can be used to set the options
and create the tournament file.
  Actual loading of new engines is done by TwoMachinesEvent, which is
now modified to also wait for the feature timeout of the first engine.
Waiting for the matchPause is now also implemented there, after waiting
for the engines (so they can be started during the pause).
  Pairings and color assignment is now all done in an absolute
(non-incremental) way, based on a new global game-number variable
nextGame, which takes over the function of matchGame in a tourney. The
latter is now used to count games between the same players, so it can be
still used to derive the load-file indexes (again in absolute fashion).
  The next game to play is already picked in GameEnd, so it can be
decided if there is a game to be scheduled, or if we can terminate.