f353e2dacf
Do not consider calender-invitations "attachments"; do mark as "calendar". Do recognize application/ics as calendar messages. Update mime-object to expose a message part's disposition. Change the "is-attachment" heuristic to include inline parts if they have a filename parameter in their content-disposition. Note that this doesn't change things radically; the delta is +69 and -202 for ~6500 attachments.