From artemis Fri Jan  4 18:24:46 2008
From: Dmitriy Morozov <morozov@cs.duke.edu>
Date: Fri, 04 Jan 2008 13:16:44 EST
State: new
Subject: Thread messages by In-Reply-To
Message-Id: <b7cdd0ec985471b7-0-artemis@metatron>

Artemis is threading messages by References header, and assumes that
there is only one element there. It should thread messages by
In-Reply-To header (and set it accordingly), and either ignore
References, or set it be equal to In-Reply-To.