Update mob AI

Mob ai is kind of outdated in places. If you’re slightly close to them, they’ll notice you, even if they’re turned around. I think it should work kind of like the warden, where they’re attracted to sound, depending on what the mob is. This could add a stealth aspect to the game, because you can hide away from all the tough mobs in an area. You can even play with this ai a bit, maybe spiders can see all around because they have more eyes, or maybe there could be mob that alerts all the others in the area when it finds you? Just an idea.