WIP - Made non-toroidal boards have an extra border of storage all
around them, that doesn't display. Allows the finite board to appear
infinite, especially for escaped gliders
Added r-pentomino pattern in data files. Made BOARD_BORDER_SIZE 50 so
that the board extends well beyond the visibile board
Changed cell storage in board to use unsigned char rather than int to
save storage size
Improved comments and removed Board.size attribute
Improved command line argument parsing, providing better error messages
and allowing options after the filename