man pages up to mdoc guidelines and fix some minor formatting glitches.
Also fixed a number of man pages to not abuse the .Xr macro to
display functions and path names and a lot of other junk.
also controlled by /var/yp/securenets).
Add -u flag to turn off the privileged port check done by yp_access();
some commercial systems (IRIX, Solaris 2.x, HP-UX, and probably others)
don't use a reserved port for submitting yppasswd updates. If we always
enforce the check, these client systems will be unable to submit updates
to us.
Document securenets support and -u flag in man page.
Like ypserv, you can compile rpc.yppasswdd to use the tcpwrapper package
instead of securenets if you want to.
