* src/attachment.cpp (Attachment::Attachment(LPDISPATCH)): New.
Construct an in memory representation of an attachment object.
(Attachment::get_file_name): New, sometimes it differs from
display name.
(Attachment::copy_to): Move logic here from mail.cpp
(Attachment::olAttachmentType): New enum.
* src/cryptcontroller.cpp (CryptController::collect_data): Move
out attachment handling. Use new data from mail object.
* src/mail.cpp (copy_attachment_to_file): Moved into attachment
class.
(Mail::updateOOMData_o): Collect data of attachments, write
out mail to tmp file to do serialization.
(Mail::checkSyncCrypto_o): For now disable sync for attachments.
(Mail::isMultipartRelated): New. Moved from mimemaker.
(Mail::plainAttachments): New data object to carry attachment data.
* src/mailitem-events.cpp (SEND): Directly encrypt. Don't wait
for AfterWrite.
* src/main.c (read_options): Remove syncEnc override.
* src/mimemaker.cpp (write_attachments): Use mail object.
(add_body_and_attachments): Use mail object.