Instead of returning -1 from nasm_token_hash, set tv->t_type to
TOKEN_ID and return TOKEN_ID, since that's what stdscan.c wants to do
with it anyway. This allows us to simply tailcall nasm_token_hash().
Finish the perfect hash tokenizer, and actually enable it.
Move stdscan() et al to a separate file, since it's not needed in any
of the clients of nasmlib other than nasm itself.
Run make alldeps.
