* I had alphabetized the --configure options in the --help output

awhile back, but Shantonu added --enable-apop just under --enable-pop.  Put it
in alphabetical order and clarified what --enable-apop does vs. --enable-pop and
--with-krb4.  Also changed --with-mts help line from "mail transport agent" to
"mail transport agent/service" so the 's' in "mts" doesn't seem to come out of
nowhere.

* Added two steps to "releasing nmh" in README.developers.  After
making the tarball, it's a good idea to diff the tree vs. the CVS tree to make
sure no files got left out, and then to chown the files so that they're owned by
root, preventing a Trojaning attack by a malicious remote user with a UID
matching yours.