ChangeLog

27.03.2019 
 - imap::statistics() method: Add optional unseen, uidnext, uidvalidity flags. (terminator356)

26.03.2019 
 - Add imap fetch_messages method. (terminator356)

12.03.2019 
 * From github user terminator356:
 - Fix exception on lower case letters: "Bad hexadecimal digit" in quoted_printable::decode().
   Convert the two characters to uppercase before checking.
 - Complete mailbox_stat_t statistics: messages_recent, messages_first_unseen,
    uidnext, uidvalidity. This REALLY helps with client message caching.
 - Add several new commands in imap.hpp, several do not select() first, for speed:
    mailbox_stat_t select_mailbox(): Exposes the protected select().
    mailbox_stat_t examine_mailbox(): Examine a mailbox.
    void fetch_message(): Has 'is_uid' parameter meaning 'message_no' param is a uid.
    void remove_message(): Has 'is_uid' parameter meaning 'message_no' param is a uid.
    void search_messages(): Has 'want_uids' parameter meaning return uids.
 - Add a new line_len_policy_t value: VERYLARGE = 16384. Required for certain received messages.
 - Add a separate '_decoder_line_policy' besides '_line_policy' to all objects.
   This allows a separate very large decoding policy while keeping a standard encoding policy.