uniquify xids; spell my name & address correctly; use yp.h instead of

uniquify xids; spell my name & address correctly; use yp.h instead of
yp_prot.h and deal with subsequent structure element name and type changes;
deal with xdr_domainname() and friends changing types; rename service
functions to *_2x() since they have non-standard calling interfaces; add
usage(); flush /var/yp/binding/ directory at startup; prefer talking to
a ypserv on the localhost