Changes in Arasan 12.2:
1) Somewhat complex trade scoring has been removed - in favor of just
adjusting piece values.
2) More aggressive futility pruning, margin is adjused at 1/2 ply increments.
3) Changes to extension/pruning logic. LMR now done after futility. Extra
LMR is done at high depths/move counts.
4) King safety scoring changed - open files are now scored separately,
score is based on opposing Rook + Queen count.
5) Bishop pair score reduced (but increases in endgame).
6) Changes to pawn scoring: outside pawn & doubled pawn scores reduced.
7) Outside pawn calc is done via a table, like Crafty does.
8 ) Penalty for own pieces ahead of passer; somewhat reduced bonus for rook
9) EGTB values are no longer hashed (seemed to cause problems).
10) Minor GUI fix: remove trailing junk after game description.