Add a cover letter for multi-patch Pull Requests

[dscho]

At the moment, patch series are sent without a cover letter.

It would be really great if a patch series consisting of more than one patch could have the initial comment of the Pull Request as a cover letter. Maybe even with the link to the original Pull Request appended at the end of the cover letter?

This would also make for a fine mail to use in the "In-reply-yo" header instead of the mail containing the first patch...

[rtyley]

Yep, this on my todo list! I think I agree with everything in your description, including the In-Reply-To: header obviously.