[PATCH 04/15] parsemail: Extract building the list of mail references

[Finucane, Stephen]

> We'll need to figure out whether the mail we are parsing is the root of
> the thread to automatically build series, and we'll need the list of
> references for that.
> 
> Signed-off-by: Damien Lespiau <damien.lespiau at intel.com>

While you didn't write this code initially, it would be incredibly useful to add some documentation on what this is doing why (i.e. a link to RFC822, RFC2822 and/or RFC5822 that defines how these fields work). I can add them in a follow up commit if not.

Acked-by: Stephen Finucane <stephen.finucane at hotmail.com>