Edit Chainsaw codes

Thanks for helping me Assassin, but I decided to take a different approach to this. It's more work, but I am going to modify all monster scripts that counter all attacks AND that are not immune to instant death to exclude tools from a counter attack. There really aren't that many monsters that fit this description. I think I can at least cut the chances of seeing this bug to a minimum. After all, I do actually like the slice effect with the Chainsaw!