The 'try' impl for 'Outcome' allows the '?' operator to be used with
'Outcome' values. This is likely to make 'FromRequest' and 'FromData'
implementations more ergonomic.
This commit also expands the 'IntoOutcome' trait. It is now
implemented for 'Option'. It also now includes an additional
'or_forward' method.
This commit includes two major changes to core:
1. Configuration state is no longer global. The `config::active()`
function has been removed. The active configuration can be
retrieved via the `config` method on a `Rocket` instance.
2. The `Responder` trait has changed. `Responder::respond(self)` has
been removed in favor of `Responder::respond_to(self, &Request)`.
This allows responders to dynamically adjust their response based
on the incoming request.
Additionally, it includes the following changes to core and codegen:
* The `Request::guard` method was added to allow for simple
retrivial of request guards.
* The `Request::limits` method was added to retrieve configured
limits.
* The `File` `Responder` implementation now uses a fixed size body
instead of a chunked body.
* The `Outcome::of<R: Responder>(R)` method was removed while
`Outcome::from<R: Responder(&Request, R)` was added.
* The unmounted and unmanaged limits are more cautious: they will only
emit warnings when the `Rocket` receiver is known.
This commit includes one major change to contrib:
1. To use contrib's templating, the fairing returned by
`Template::fairing()` must be attached to the running Rocket
instance.
Additionally, the `Display` implementation of `Template` was removed. To
directly render a template to a `String`, the new `Template::show`
method can be used.
Sergio Benitez