Increase MaxDepth default value to 128

[eduherminio]

Non regression, so I'll just take it.

10+1

Score of Lynx 983 - depth 128 vs Lynx 976 - net 8: 564 - 528 - 293  [0.513] 1385
...      Lynx 983 - depth 128 playing White: 288 - 252 - 152  [0.526] 692
...      Lynx 983 - depth 128 playing Black: 276 - 276 - 141  [0.500] 693
...      White vs Black: 564 - 528 - 293  [0.513] 1385
Elo difference: 9.0 +/- 16.2, LOS: 86.2 %, DrawRatio: 21.2 %
SPRT: llr 0.586 (19.9%), lbound -2.94, ubound 2.94