Added stack state to the board (includes move history, captured pieces, en passant locations, and castling rights). As a result, Move.captured no longer exists.
Fixed error in {ASSERT/EXPECT}_{TRUE/FALSE} macros.
Implemented makeMove and undoMove, and their corresponding tests. Castling has been excluded for now while I figure out how to deal with the whole idea of it.
Made the error message for failing to load the log file more informative.