[opensuse-boosters] Threads in hermes mails

Hey, I love hermes mails, but I would love them even more if the mails for one request where all grouped in a thread. So here's my completely untested attempt for this (and I'm not sure I'm still fluent in perl, so there might be some stupid errors). Is there any way to easily test this kind of things? Cheers, Vincent -- Les gens heureux ne sont pas pressés.