Z:gnu-gibbon--eb4ce7-Recognized values for FORMAT a/en

Recognized values for FORMAT are 'SGF' for the Smart Game format (used by Gibbon and GNU backgammon), 'GMD' for the Gibbon Match Dump format, 'Jellyfish' and 'JavaFIBS'. Formats are case-insensitve and you can abbreviate them as long as they are unique. \