Good news and bad news: good news is that the memory leaks are pretty
much gone, down to 110 bytes or so, of which I think about 50 are caused
by SDL.  However, it doesn't work because of something that I changed,
but I'm really not sure why.  There are always 401 enemies in the character_list,
and none of them seem to be valid.  It must be that the pointer to
a good enemy is getting deleted for some reason.  I'll look into it.