imap-proto 0.10.0

This release contains one incompatible change: all fields of the Address type as well as some fields of the Envelope type are now &[u8] instead of &str. It turns out that parsing these as UTF-8 was, unfortunately, too restrictive for parsing messages in the wild. Thanks to @link2xt for investigating and fixing this.

• Allow arbitrary bytes for some string fields (#63, thanks to @link2xt)
• Allow invalid continuation responses as seen from Yandex (#68, thanks to @dignifiedquire)