All embedded information now lives under the original part.

All embedded information now lives under the original part.

Resolves Ticket #8296; Ticket #8629

Don't replace the original part with the embedded information. This
ensures we can always uniquely access the original data if necessary.
Also allows us an easier method to show status messages for related data
and allows us to do fancier things like wrapping entire parts with
colored borders (i.e. multipart/encrypted, multipart/signed).

Fixes problems with S/MIME encrypted/signed messages.