Modified varible names to not have **. An EmacsLisp thing.
Style corrections.
Changed color of the "fence" to "brown".
Changed the animals character to 'm'.
Renamed the original evolution function to evolution-start.

Added (inhibit-read-only t) to evolution-start, since it
now uses the mode.
Use SPACE to start simulating.
The fence's color can now be configured with a variable.