Peripheral 1.1.3

Changelog

• Added extended null move pruning.
• UCI additions
  • position kiwipete
  • seldepth (furthest depth reached by Qsearch)
  • Visited nodes are now correctly counted (about 3x as many)

I have also tried NMP, and several common optimizations for NMP and NMR, but they did not gain against the basic null move reduction algorithm. It might be worth to retry these optimizations later, when the engine is hopefully stronger overall.

SPRT

Score of peripheral dev vs peripheral 1.0.0: 158 - 77 - 68  [0.634] 303
...      peripheral dev playing White: 81 - 38 - 33  [0.641] 152
...      peripheral dev playing Black: 77 - 39 - 35  [0.626] 151
...      White vs Black: 120 - 115 - 68  [0.508] 303
Elo difference: 95.2 +/- 35.5, LOS: 100.0 %, DrawRatio: 22.4 %
SPRT: llr 2.92 (100.9%), lbound -2.25, ubound 2.89 - H1 was accepted

Full Changelog: v1.0.0...v1.1.3