Builds on top of#274

Handles all of the straightfoward changes in building on top of thehttp crate instead of the bespoke internal definitions now thathttp is reasonably stable. This handles porting

• Vec<tiny_http::Header> ->http::HeaderMap
  • Included droppingtiny_http::Header andtiny_http::HeaderField
• tiny_http::StatusCode ->http::StatusCode
• tiny_http::Method ->http::Method
• tiny_http::HTTPVersion ->http::Version
• String URL paths ->http::Uri

closes#278closes#100

• Doesother&str parameter really need to have static lifetime inHeaderField::equiv? #278
  • http::header::HeaderName has aPartialEq<&'a str> that's not the'static lifetime (although fixing the issue directly is also trivial)
• Headers as HashMap rather than Vec<Header>? #100
  • http::HeaderMap is a customized hashmap specifically for headers, so I'd imagine the performance is good

Future work

I might get around to making some of the changes in this PR, but the main missing pieces now arehttp'sRequest andResponse types along with their correspondingParts andBuilders. TheRequest andResponses have some more significant differences, so potentially just easing conversion between them