V1.2.0 Minimax AI update

Minimax algorithm with 4 plys implemented, press B to use the best move of this AI for the player's turn.

v1.1.0

New Chess version 1.1.0 contains checkmate as win condition, castling, and en passant, and additionally has 'r' to use the random move ai bot. This is as close to the original game as its going to get (outside of the 50 fold move and possibly 3 fold repetition).

v1.0.0

Basic version of Chess for the terminal command line on Windows. At this moment, only supports a single computer PvP mode and does not support castling or en passant. Also, this version of chess is a capture king to win variant.