Music packet tweak, uint size was off.

I'd been injecting what I thought were large IDs before, but I was mistakenly sending both block and song as one value prior to changing chocobo_music into change_music, and so I derped the size in that commit.

I've also mapped a lot of the music tracks now, tossed that into the documentation dir so inclined persons can add to it.
steel sings, blades dance