Move stuff out of the way
Define common constants
Add shifts
Pregenerate knight attacks
Pregenerate king attacks
Use lists instead of tuples
Pregenerate rank attacks
Pregenerate file attacks
Pregenerate diagonal attacks
Implement next_bit() function
Add list of square names
Generate pseudo legal moves
Implement is_attacked_by routine
Generate simple pawns moves
Pregenerate pawn movements
Add pawn_moves_from()
Implement pawn attacks for is_attacked_by()
Implement population counting
side_to_move -> turn
Introduce king squares