Add followup move history counters
Add followup move history counters

Pure CM didn't help -- maybe this is better?

ELO   | -1.95 +- 6.57 (95%)
SPRT  | 30.0+1.00s Threads=1 Hash=64MB
LLR   | -1.64 (-2.94, 2.94) [0.00, 5.00]
GAMES | N: 7120 W: 2343 L: 2383 D: 2394

jwatzman/nameless-chessbot,jwatzman/nameless-chessbot