completed pawn rules + bug fixes for 4-char-moves

fixed crucial bug where both players could move at the same time + added pawn rules (TODO: en passant)

completed eval_move

interface for retrieving locations when using short algebraic notation

added network messages for check and checkmate

prepared code base for implementing rules

implemented castling (without validation)

(0) -10 -7 +7 +10 +30 tip

mercurial