[PATCH 4/4] show: Rewrite show_message_body to use the MIME tree interface.

[Dmitry Kurochkin]

Hi Austin.

I enjoyed reviewing this patch.  It is a pleasure to see how complex and
confusing code becomes much smaller and cleaner.

I still have some questions with the new code.  It seems confusing to me
that part_content is called first and then go envelope headers.  But I
this is just the first step of the rewrite, right? :)

The only comment I have:

+    format->part_content (part);

For all other format members that are function pointers, we have a check
for NULL.  Perhaps we should add it here as well?

Regards,
  Dmitry