Tweak fairy piece values

Tweak fairy piece values

capablanca STC
LLR: 2.96 (-2.94,2.94) [0.00,10.00]
Total: 344 W: 187 L: 96 D: 61
http://35.161.250.236:6543/tests/view/5cd99b016e23db34f4206ab0

capablanca LTC
LLR: 2.97 (-2.94,2.94) [0.00,10.00]
Total: 345 W: 192 L: 99 D: 54
http://35.161.250.236:6543/tests/view/5cd9ab846e23db34f4206abd

courier STC
LLR: 2.96 (-2.94,2.94) [0.00,10.00]
Total: 162 W: 92 L: 18 D: 52
http://35.161.250.236:6543/tests/view/5cd99b206e23db34f4206ab3

courier LTC
LLR: 2.95 (-2.94,2.94) [0.00,10.00]
Total: 144 W: 80 L: 11 D: 53
http://35.161.250.236:6543/tests/view/5cd9ac0b6e23db34f4206abf