scrabble: validate scoring & move generation against real GCG games

Replay 17 real tournament games (cross-tables.com, including the 700+ club) and
check, move for move, that:
  - ScorePlay reproduces the protocol score and running total exactly;
  - the move generator produces every dictionary-valid played move with that score.

The GCG parser handles coordinates (across/down), blanks (lowercase), played-through
tiles ("."), passes/exchanges, challenge bonuses, end-game rack adjustments and phony
withdrawals ("--", un-applied). Uses the committed dawg/en_sowpods.dawg.

scrabble/testdata/anno28478.gcg

@@ -0,0 +1,29 @@
+#player1 David David Poder
+#player2 Bruce Bruce D'Ambrosio
+>David: ?DEEEMS 8H SEEDMEn +74 74
+>Bruce: OVW 7G VOW +28 28
+>David: AILNPSU F6 PAULINS +77 151
+>Bruce: HI 7M HI +19 47
+>David: BBIJ 12B JIBB. +32 183
+>Bruce: CNO 13A CON +23 70
+>David: FFO 6I OFF +23 206
+>Bruce: IRTUV E2 VIRTU +20 90
+>David: EGU 4D G.UE +10 216
+>Bruce: LT B12 ..LT +22 112
+>David: AZ 6N ZA +62 278
+>Bruce: AEEILUY -AEEILUY +0 112
+>David: ?AAEERS 15A S.EARAtE +122 400
+>Bruce: AD 14F DA +15 127
+>David: EILOPRT 3G POLITER +83 483
+>Bruce: ADEIMRT 13G READMIT +77 204
+>David: IQ 2J QI +64 547
+>Bruce: NU 14K UN +8 212
+>David: AEKT 15L KETA +51 598
+>Bruce: GO H1 GO. +12 224
+>David: HLORW 1K WHORL +51 649
+>Bruce: Y I5 Y... +10 234
+>David: EX 4K EX +43 692
+>Bruce: AEINRST 10F .NERTIAS +60 294
+>David: ACDEGNO 12L DANG +36 728
+>Bruce: INOY D6 YONI +16 310
+>Bruce:  (CEO) +10 320