initial commit
xboard protocol
initialize board
use lowercase file names
rename executable in Makefile; record piece info in Board
add hash_code in Board
move and unmove
static values
generate moves for king
generate moves for rooks
generate moves for horses
clear move counter at the beginning
removed dependencies on C++11; fixed a bug in board class
remove Java legacies
move header
generate moves for cannons
generate moves for elephants (unfinished)
generate moves for elephants
generate moves for assistants
generate moves for pawns