[SM-STABLE] Fix for problem in mime.php

[Seth E. R. <se...@mi...>]

Attached is a small patch to add support for Content-Type="multipart/mixed"
in mime.php .  This content type seems to be used in some email newsletters
and Outlook uses it when you send an HTML email with an attachment.  I'll
also put this on the patch tracker on SourceForge.

Thanks,
Seth.
-- 
Seth E. Randall
IT Support Specialist
Missoula Federal Credit Union
se...@mi...