Fixes:
- dnsbl_filter: support DNSBL servers that do not emit TXT records
- email_lib: cure IMAP Structure Descriptions indicating a mail size 2 bytes larger than it is
- imap: cope with truncated EML files
- exmdb: delete leftover stray ROLLBACK statement
- ews: cure null dereference in tInternetMessageHeader::parse
- ews: use vmime parser to break down IMHs and reset an Apple workaround for "From" lines
Changes:
- emsmdb: attempt to synthesize PR_SENDER_ADDRTYPE & PR_SENT_REPRESENTING_ADDRTYPE when they are missing (also warn when those properties are deleted)