Split board.load_from_file to load_from_ascii;
Add board.width,height accessors;
Add Wall class with ImmovablePiece superclass;
Prevent move_solid_inhabitant from moving an ImmovablePiece;
Add GAME_ASCII for tile with both a goal and the player;
Create level-001 from Wikipedia GIF;
Create basic spec for Board.load_from_ascii based on level-001