gotham 0.7.0

Crates:

• gotham 0.7.0
• gotham_derive 0.7.0
• gotham_middleware_jwt 0.7.0
• gotham_middleware_diesel 0.4.0

Starting with this version, directly importing the derive macros from the gotham_derive crate is deprecated. Use gotham::prelude::* instead.

Changelog:

• Send state to the session backend and allow it to return futures (#468)
• Re-export the mime crate and all gotham_derive macros
• Add AsyncTestServer (#552, #553, #555)
• Introduce new features session, http2 and testing (all enabled by default)
• Remove rustls feature from the default features
• Start functions now return a result (#568, #571)
• Allow access to the inner error of a HandlerError (#575)
• Add a prelude module that re-exports traits and derive macros (#567)