If the RECIPIENTTOLIST header fields exists and the RFC822 header field
does not exist, that means the original RFC822 "To" field was not MIME-encoded,
which is the majority of email. The routine that converted an smbmsg_t to an
RFC822 header did not use this new field however (ignored it). Whoops. So
multiple recipients were reflect in the To field and the original destination
address(es) in the To field weren't passed on either. Thanks, Frank!