(refactor) AroundMiddleware produce Handlers instead of being Handlers.
(feat) Show impl for Response.
(feat) Example AroundMiddleware.
(fix) Remove Send bound on Errors.
(feat) Implement Decodable and Encodable for Url.
Merge pull request #166 from reem/refactor/around-middleware

Refactor AroundMiddleware to produce handlers instead of being Handlers
Merge pull request #175 from reem/feat/decode-encode-url

(feat) Implement Decodable and Encodable for Url.