* Update 'tokio', 'tokio-rustls', and 'hyper'.
* Remove unused dependencies on some `futures-*` crates.
* Rework 'spawn_on', which is now 'serve'.
* Simplify Ctrl-C handling.
Use I/O traits and types from 'tokio-io' as much as possible.
A few adapters only exist in futures-io-preview and use
futures-tokio-compat as a bridge for now.
* body_string_wait and body_bytes_wait are removed; use `.await` instead
* `dispatch()` is now an async fn and must be .await-ed
* Add `#[rocket::async_test]` macro, similar in purpose to `tokio::test`
* Tests now use either `rocket::async_test(async { })` or
`#[rocket::async_test]` in order to `.await` the futures returned
from `dispatch()` and `body_{string,bytes}()`
* Update 'test.sh' to reflect the tests that should be passing.
Broken:
* Cloned dispatch and mut_dispatch() with a live previous response now both fail, due to a (partial) check for mutable aliasing in LocalRequest.
* Some tests are still failing and need example-specific changes.
Paolo Barbolini
Jeb Rosen
Jacob Pratt
Sergio Benitez