v1.6.1 Exploding cars, zombie/civilian interaction

I decided to modify the behavior of civilians and zombies.

Previously, civilians didn't do much besides randomly running around and zombies didn't pay any attention to them (although they are human and thus can be as good of a meal as the main character).

So right now, zombies are chasing and attacking civilians and civilians are trying to run for their lives.

I added a civilian counter, in case somebody would like to accept the challenge of saving all the innocents (instead of using them for target practice;).

Cars are now exploding (with awesome sound and animation;) and can hurt both humans and zombies.

I also did a small refactor of the main characters code.

Oh, and the big dumpster is now making sound when you shoot at it ;)