[WIP] Split integrations into separate crates

[fabianfreyer]

See discussion in #234. This is a first attempt at splitting out some of the integrations - I'm not sure this is the right way though.

• Split out actix-web
• Split out gotham
• Split out rocket
• Split out iron

[djc]

This looks great! I'd like to move the actix tests into askama-actix as well. Also I think as the author of most of the code in askama-actix, I think I should be part of the authors in the crate metadata? Also it looks like askama-actix uses extern crate more than necessary in 2018 Rust.

[fabianfreyer]

This looks great!

Hmm, the tests don't pass yet though, it currently fails with:

error[E0277]: the trait bound `tests::HelloTemplate<'_>: actix_web::handler::Responder` is not satisfied
  --> askama_actix/src/lib.rs:79:55
   |
79 |         let mut srv = test::TestServer::new(|app| app.handler(|_| HelloTemplate { name: "world" }));
   |                                                       ^^^^^^^ the trait `actix_web::handler::Responder` is not implemented for `tests::HelloTemplate<'_>`

I'd like to move the actix tests into askama-actix as well.

Yep, this sounds like a good idea!

Also I think as the author of most of the code in askama-actix, I think I should be part of the authors in the crate metadata?

Of course! I hadn't done much in the Cargo.toml yet - just poking around to make sure this approach works for now.

Also it looks like askama-actix uses extern crate more than necessary in 2018 Rust.

Ah, good point, I'll remove that

[djc]

This was finally fixed in #255. Thanks for working on it with me!