Make bear range circular (again).
Sane variable naming (again).
Remove self.pfinitialvalue (won't work well with variable costs).
Make bears consider terrain difficulty (again).

This makes bears avoid forests, which is silly.
Linewrap some overly long conditions.
Create non-hunting Bear.move() function.
Bears wander about if not chasing the player.
Remove assorted trailing whitespaces.
Merge pull request #22 from FLHerne/master

Bear pathfinder tweaks