(Predefined Aux-Item Types): Introduced some
hints for client authors and clarified the description of some
aux-items based on experiences from writing "komimportmail";
changed definition of mx-in-reply-to to specify that is should
really be the Message-ID used for threading, regardless of which
header line that supplied it. Marked mx-allow-filter and
mx-reject-forward obsolete.
(komimportmail Aux-Item Types): new node describing
the aux-items introduced by this importer.
(Importing and Exporting E-Mail): rewrote most of the chapter,
using experience from "komimportmail". Removed text about
export, as it was rather naive.