Oct 27, 2018: Version v4.1
  - Added quiet move generator.
  - Improved late move reduction.
  - Increased density of transposition table.
  - Added `hashfull` metrics in UCI mode and cache hits in REPL mode.
  - Improved endgame evaluation for positions with opposite-colored bishops.
  - Many small improvements and tweaks.

Jan 8, 2016: Version v4.0
  - Improved search depth on typical time controls.
  - Many more optimizations and position evaluation tweaks.

Oct 26, 2015: Version v3.1
  - Fine-tuned internal evaluation parameters and weights.
  - Updated mobility evaluation to take into account pinned pieces.

Oct 11, 2015: Version v3.0
  - Improved root move ordering.
  - Improved late move reduction in search.
  - Simplified quiescence search.
  - Implemented King with pawn vs King with pawn endgame evaluation.
  - Added pawn square rule and unstoppable pawn detection.
  - Replaced standard Go sort with faster shell sort to speed up move ordering.
  - Optimized principal variation to avoid memory garbage collection.
  - Doubled maximum depth from 32 to 64 plies.
  - Imporved unit test coverage.
  - Fixed nasty bug in King with pawn vs King endgame.
  - Fixed rare condition resulting in infinite loop.

May 11, 2015: Version v2.1
  - Fixed cache allocation to reuse existing cache (if any) when starting new game.
  - Added UCI Hash option to be able to specify hash size (32Mb to 1Gb, default 256Mb).
  
May 2, 2015: Version v2.0
  - Refactored quiescence search.
  - Revamped positions cache (aka transposition table) code.
  - Doubled default cache size to 256Mb.
  - Implemented more conservative time allocation for floating time control.
  - Adjusted king safety evaluation for positions with opposite color bishops.
  - Fine-tuned some evaluation parameters.
  - Added "book" command to REPL.

Dec 14, 2014: Version v1.0
  - Initial release.
