fix wildcard MX handling (option W no longer needed); fix

fix wildcard MX handling (option W no longer needed); fix
process title when using cached connection; many minor fixes

SCCS-vsn: usr.sbin/sendmail/src/READ_ME 6.3
SCCS-vsn: usr.sbin/sendmail/src/usersmtp.c 6.5
SCCS-vsn: usr.sbin/sendmail/src/main.c 6.14
SCCS-vsn: usr.sbin/sendmail/src/envelope.c 6.6
SCCS-vsn: usr.sbin/sendmail/src/conf.h 6.6
SCCS-vsn: usr.sbin/sendmail/src/domain.c 6.3
SCCS-vsn: usr.sbin/sendmail/src/version.c 6.18
SCCS-vsn: usr.sbin/sendmail/src/sendmail.h 6.8
SCCS-vsn: usr.sbin/sendmail/src/TODO 6.4
SCCS-vsn: usr.sbin/sendmail/src/readcf.c 6.6
SCCS-vsn: usr.sbin/sendmail/src/deliver.c 6.14
SCCS-vsn: usr.sbin/sendmail/src/conf.c 6.13