Forwarding attachments as-is and without autoview

[jaromil]

Nice to have HTML rendered, but its not handy to switch autoview on/off when forwarding it to someone as-is without the HTML rendering in TXT. I noticed the only way to forward selectively attachments this way is by piping them to other programs in mutt. So this issue suggests to implement a jaro forward function that takes from stdin, forwards an attachment taken from stdin and that is properly mime-encapsulated and takes one or more addresses on the commandline as people to send it to.

There won't be completion on the commandline when using this command, but then going to outbox one can add more addresses and with completion working.