Log Message:
Update to 20181027. Changes:

- Implement SMTP "STARTTLS" and POP3 "STLS", relying on \ 
sslserver's UCSPI-TLS.
  Derived from s/qmail's implementation.
- Catch up to s/qmail's base64 implementation.
- Implement POP3 "CAPA" verb for POP3.
- Require admin to describe child program in control/{pop3,smtp}capabilities.
- Fix regression from qmail-popup: sleep after auth failure for SMTP only.
- Update authup(8) manual page.

pkgsrc changes:

- Replace security/stunnel dependency with net/ucspi-ssl.