Content-MD5 ?

    test: multiple field w/ the same name must be preserved (Received:)
    
    codecs bench/optimization
    
    MimeEntity cpyctor & op=
    
    b64 & qp examples converted to File::iterator
    
    BUG: istring::find e istring::compare NON sono case insensitive
    
    override MimeEntity::write for binary entities (application/* etc.) so
    we don't need to store files in memory but we can just print them out
    when needed

    usare size_t(in config.h)  invece di unsigned int

    opt: create boundaries using char that are not allowed for
    base64 encoded stuff

    docs docs docs...    
    
    coding style check
    
    MMFile and StdFile tests

    MMFile and StdFile must be handled by configure
    
    inline keyword where needed
    
    omimeentity_iterator:
        copy(beg,end,omimeentity_itarator<char>(entity))
    imimeentity_iterator:
        imimeentity_itarator beg(entity), end;
        copy(beg,end, outputit)

    char_type clean
    error handling/codes
    
    message/external-body
    
    - message-id part-id
      - multipart/related

    rfc822 update:
        - rfc 1123
        - rfc 2822 (822bis)

    todo:
      -? usenet msg format test
    rfc822:
      - DateTie > < >= <= == !=
      - DateTime() ctor == Now()
      - tutte le classi devono ritornare la stringa di inizializzazione se
        sono state costruite tramite stringa di input in modo da minimizzare
        la differenza tra contenuti parsed e quelli reali
      - field "\"" quoting support
      
      -? field << Charset(IS08859-1) << base64str << 
          Charset(ISO8859-4) << 34 << 55;     
        field.append(Charset(), base64str);

    ::::
      - uuencode binhex
      - RFC2231
      - check rfc2047

      S/MIME
      PGP/MIME