Support parsing e-mail replies

[TuhinNair]

Hey @mdecimus!
First of all, thank you for all your work on the AMAZING email crates you've contributed to the rust ecosystem. I rely on them so frequently!

While sending replies, email clients frequently append older messages at the bottom of the text or html body. They use non-standard formats to delineate the new reply text and the older messages.

Currently when I parse the text or html body using the mail-parser crate it includes the appended context. I'd like to parse just the new content i.e the visible part of the reply.

It's a difficult problem to solve but I've found helpful libraries in other languages. Before complicating my setup I wanted to check if this was possible with mail-parser or within the rust ecosystem. Here's what I found:

1. https://github.com/willdurand/EmailReplyParser [PHP]
2. https://github.com/github/email_reply_parser [Ruby]
3. https://github.com/t2bot/node-email-reply-parser [JS]

Thank you for your help :)

[mdecimus]

Hi @TuhinNair ,

Currently mail-parser just parses MIME parts and converts HTML parts to plain-text and vice-versa. At the moment I am working on the SMTP server and refactoring the JMAP/IMAP servers but I'll leave this issue open and whenever I have some time I'll implement this feature.

Cheers.

[i1Fury]

Bumping this issue :)

[prosammer]

I would also love to see this! Thanks for your work @mdecimus