hidden behind #ifdef's, since no OPT code number has yet to be assigned
by the IANA. They are also not quite complete in all regards; VIEW
options are understood and ignored. ZONE options are understood and
acted upon, though some of the error cases aren't quite right.
Remove doubled isc_mem_stats in dighost.c
Update todo list.
Change literal 255's to DNS_NAME_MAXWIRE in name.c
dc570b92f6