Envelope

- fix: loading headers not encoded with utf-8
- fix: better S/MIME detection 29
- drop Python 3.9 support
- SMTP HELO FQDN

- experimental [XARF](http://xarf.org/) reports reading
- disguised addresses parsing

- fix 24 stable locale
- allow `file-magic` instead of `python-magic` package be installed on the system (25)
- fix GPG signing when attaching file with name longer than 34 chars (19)

- CHANGED: `Envelope(sender=).sender()` alias REMOVED because to the unambiguous naming clash between the `From` and the `Sender` e-mail header. Use `Envelope().from_(...)` and `Envelope().header("Sender", ...)` instead. Pity that 'from' is a reserved keyword, "from_" looks bad.
- CHANGED: `Envelope.default` instance REMOVED because explicit is better than implicit. For setting defaults use `Envelope().copy()` instead
- CHANGED: explicitly specifying encryption keys prevents encrypting for other recipients
- GPG encryption for arbitrary keys only possible 9 14
- CHANGED: Optional parameter "email_or_list" renamed to "email_or_more" (methods `to` and friends)
- When setting recipients, apart from list other iterables (tuple, generator, set, ...) may be used
- fix: when signing key fails, do not sign with the default GPG private key
- S/MIME insecure Rand PRNG removed 18

- disable validate_email module blacklist updater 17
- SMTP envelope MAIL FROM address 16
- SMTP exposes timeout 20 , attempts, delay
- SMTP re-connect on every error 21
- smtp.quit() exposed 5

- group syntax is no more reported as erroneous (ex: undisclosed-recipients:;)