More AI and more sounds

Made some improvements and fixes to the enemy AI controller, and started adding sounds to various things, mostly enemies. There is now sound and a visual when you hit super armor. I'll slowly be adding more sound effects here and there, and possibly changing the cave BGM.

I also finally got myself motivated enough to work on the new character sprite! The next update may feature several changed and/or WIP animations for the Kobold, who I've taken to calling Ko.