[PATCH] add authproxy option

[Luke Kenneth Casson Leighton]

many apologies: as you can see i am still experimenting with prayer
webmail and this setup... which appears to completely bork up the
formatting of messages that it imports... and i had errors which
indicated, to all intents and purposes, that the message hadn't been
sent, so i retried it... oops.

i'll make use of sendmail, directly, that should do the trick.

sorry all!

l.