More Evaluation impovements

Adds even more evaluation improvements:

• Value bishop pair
• Rework of king endgame behavior

Evaluation improvements

Changes since v0.5.0:

• Remove penalty for getting queen out early
• Encourages trading down when ahead
• Tweak to promote making luft
• Pawn structure analysis (passed pawns, isolate pawns and defended pawns)
• Bonus for rooks on (half) open files

Transposition Tables

Adds a transposition table.
The transposition table is used by both the full and quiescent search (though only full results are stored in it).

(~65 elo improvement on the short time control)

50 move rule detection

This version adds detection of 50 move rule and auto claims a draw once it is reached.

Repetition detection

This release adds zobrist hashing and a repetition table.
The search uses this to assign a draw evaluation upon a 1 fold repetition.
This logic slows down move generation, however, the search can exit earlier when repetitions are detected which provides a slight increase in the search depth that is achieved.

Quiescent Search

This release adds quiescent search. This means that at the end of every search it performs an additional search for each leaf node to evaluate all possible capture moves (up to some max depth or until no captures are possible).

This version plays significantly better as most of the blunders in previous versions seemed to be caused by halucinations at the end of the search due to not evaluating captures. (estimated elo increase of 250 to 300 points).

Improved Endgame play

• Engine now uses interpolation between middlegame and endgame piece square tables.
• Mop up score improved significantly. (now only losses due to repetition on some occasions)

Initial engine

An initial chess engine implementation which uses:

• Based on movegeneration using bitboard chess implementation
• Using itterative deepening and minimax
• Using a simple evaluation with unoptimized piece value tables, a simple king safety score and a very unstable mopup score

Full Changelog: https://github.com/BasJansweijer/ChessBitBoards/commits/v0.0.1