Improved visual experience a little.

Now using state to grow grid if needed.
Changed to Courier font.
Changed the 'O' to a 16 pointed asterisk, which I think looks more like a living thing.
Empty cells have the foreground color changed to white, instead of changing to blank or
empty string. This makes all cells equal in size.
Added border between cells.
Decreased iteration frequency to 2fps.
Also changed from sending ranges around, to tuples of lower and upper.