clean up log levels; allow IDA-style split header/envelope rewriting;

clean up log levels; allow IDA-style split header/envelope rewriting;
extend arpatounix with more zones (but is this even needed?)

SCCS-vsn: usr.sbin/sendmail/src/usersmtp.c 6.8
SCCS-vsn: usr.sbin/sendmail/src/headers.c 6.6
SCCS-vsn: usr.sbin/sendmail/src/recipient.c 6.9
SCCS-vsn: usr.sbin/sendmail/src/main.c 6.16
SCCS-vsn: usr.sbin/sendmail/src/envelope.c 6.8
SCCS-vsn: usr.sbin/sendmail/src/parseaddr.c 6.13
SCCS-vsn: usr.sbin/sendmail/src/arpadate.c 6.5
SCCS-vsn: usr.sbin/sendmail/src/err.c 6.5
SCCS-vsn: usr.sbin/sendmail/src/version.c 6.23
SCCS-vsn: usr.sbin/sendmail/src/savemail.c 6.5
SCCS-vsn: usr.sbin/sendmail/src/srvrsmtp.c 6.7
SCCS-vsn: usr.sbin/sendmail/src/util.c 6.5
SCCS-vsn: usr.sbin/sendmail/src/readcf.c 6.7
SCCS-vsn: usr.sbin/sendmail/src/deliver.c 6.16
SCCS-vsn: usr.sbin/sendmail/src/queue.c 6.11
SCCS-vsn: usr.sbin/sendmail/src/alias.c 6.10