Silly little error...it is now possible to sneak up on enemies, but
once they see you they'll continue to follow you until you get out
of their range of sight.  I would like to add a mechanism so that
they can also hear you approach, but that will be sometime in the future.
I also want to add a way to have them be aware of you, but not targetting
you, and a way to attack an unaware enemy for extra damage.
For now, I want to try to fix the odd error where the enemy's LoS isn't
displaying correctly.