Makes fireball better at breaking things

Created by: Sprok0

When a fireball hits something that isn't a mob, it will now move onto whatever it hits before exploding to increase its effectiveness at breaking things that aren't the floor. No longer will a window take like ten fireballs to break!

Adds a bit to the fireball description to make clearer that it will explode if it gets within a tile of any mobs. Makes fireball not get stopped by people lying on the ground.