Documentation update providing current support channels.
No show-stopping bugs fixed, just lots of nits.
Changes to the actual port:
Simplify handling of PREFIX.
Use autoconf.
Use DOT_LOCKING, not FLOCK_LOCKING. (IMPORTANT)
Tweak DESCR to make it more obvious that this is an MUA.
PR: 15423
Submitted by: maintainer
(lots of bug fixes, plus the port's locking is fixed, and inc will honour
a mode 775 /var/mail).
Also pacify portlint.
Submitted by: Scott Blachowicz (partially)
