This commit is a codebase-wide cleanup driven by clippy warnings. In
addition to fixing every reasonable warning, the following new
functionality was introduced:
* `Accept::new()` now takes any `T: Into<QMediaType>` iterator.
* `TempFile::is_empty()` was added.
* `HeaderMap` now implements `IntoIterator`.
This commit makes the following breaking changes:
* The `IntoCollection` trait is gone. Generics previously bound by the
trait are now bound by `IntoIterator`. This affects:
- `Accept::new()`
- `ContentType::with_params()`
- `Permission::{allow, allowed}()`
* `MediaType`, `QMediaType`, and `Allow` implement `IntoIterator`,
enabling most existing code to continue working without change.
* The inherent `HeaderMap::into_iter()` method was removed.
* The `Ok` variant in ErrorKind::Liftoff` is now `Box<Rocket<Orbit>>`.
Previously, the `NotFound` status code was used to signal many kinds of
recoverable, forwarding errors. This included validation errors, incorrect
Content-Type errors, and more.
This commit modifies the status code used to forward in these instances to more
precisely indicate the forwarding condition. In particular:
* Parameter `FromParam` errors now forward as 422 (`UnprocessableEntity`).
* Query paramater errors now forward as 422 (`UnprocessableEntity`).
* Use of incorrect form content-type forwards as 413 (`UnsupportedMediaType`).
* `WebSocket` guard now forwards as 400 (`BadRequest`).
* `&Host`, `&Accept`, `&ContentType`, `IpAddr`, and `SocketAddr` all forward
with a 500 (`InternalServerError`).
Additionally, the `IntoOutcome` trait was overhauled to support functionality
previously offered by methods on `Outcome`. The `Outcome::forward()` method now
requires a status code to use for the forwarding outcome.
Finally, logging of `Outcome`s now includes the relevant status code.
Resolves#2626.
The new examples directory...
* Contains a `README.md` explaining each example.
* Consolidates examples into more complete chunks.
* Is just better.
Resolves#1447.
Sergio Benitez