Updated copyright notices to include the year 2018.
lib-mail: message_header_hash() - add v4 that strips tabs This helps with Zimbra, which strips away trailing tabs in BODY[HEADER].
lib-mail: message_header_hash_more() - add v3 that strips spaces This helps with Zimbra, which strips away trailing whitespaces in BODY[HEADER].
lib-mail: message_header_hash_more() - refactor to use switch()
Updated copyright notices to include the year 2017.
lib-mail: message_header_hash_more() now allows input in any slices. There wasn't necessarily any guarantees that the input would be sliced in such a way that the repeating '?' would be dropped the same way every time.
lib-mail: Removed obsolete comment about message_header_hash_more() pop3-migration plugin uses this function now, so it doesn't need to be kept in sync.
lib-mail: Changed message_header_hash_more() to support any hash algorithm
lib-mail, dsync: Moved dsync_mail_hash_more() to lib-mail/message-header-hash.*