* Replace hyperx Header and Headers with our own implementation
* Remove utf8_b
* Add RFC 1522 encoder
* Fix most tests
* Throw away old tests
* Header encoding tests
* Fix slicing in the middle of a char
* Content-Disposition after rebase
* Fix the rest of the tests
* Fix useless clone clippy warnings
* Remove Headers::get_raw_mut
* HeaderName::new_from_ascii fallible API
* Tidy up HeaderName::new_from_ascii_str
* HeaderName::new_from_ascii(_str) tests
* Update dependencies (#386)
* Update dependencies and set MSRV to 1.40
* update hyperx
* Use display instead of description for errors
* Make hostname an optional feature
* Envelope from headers
* Update hyperx to 1.0
* rename builder to message
* Cleanup and make Transport send Messages
* Update rustls from 0.16 to 0.17
* Move transports into a common folder
* Merge imports from same crate
* Add message creation example to the site
* Hide "extern crate" in doc examples
* Add References and In-Reply-To methods
* Add message-id header
* Add blog posts and improve doc examples