adding OAuth

[Ken Hornstein]

>	KH: 'it looks like it only implements OAuth 1.0 (the original
>XOAUTH mechanism), and GMail now supports OAuth 2.0.'
>	And 1 still, from the output of a relay through it:
>	'050 250-AUTH LOGIN PLAIN XOAUTH2 PLAIN-CLIENTTOKEN OAUTHBEARER XOAUTH'
>
>	I may misunderstand: I think mutt and all those other scripts
>call sendmail (or whatever resident SMTP server) to send messages.  Am
>I wrong?

Like Claus said, it's configurable; because of authentication (along
with other reasons), the default configuration for nmh is to talk to
the SMTP server directly rather than submit it to your local copy of
sendmail.  As far as I know, pretty much every MUA can submit mail
directly via SMTP.  I will note that a number of people think EVERY
MUA should only submit email via sendmail; I disagree with that stance,
but what you do is up to you.

--Ken