They'd previously see the nested URI as we mutated the request. Now we
always route based on the nested URI (if present) without mutating the
request. Also meant we could get rid of `OriginalUri` which is nice.
With this you'll be able to do:
```rust
let one = route("/foo", get(|| async { "foo" }))
.route("/bar", get(|| async { "bar" }));
let two = route("/baz", get(|| async { "baz" }));
let app = one.or(two);
```
Fixes https://github.com/tokio-rs/axum/issues/101
It cleans up the docs to have the futures in their own modules as users
are unlikely to look at them. Also matches the pattern used in tower
https://docs.rs/tower/0.4.8/tower/util/future/index.html.
Added re-exports to the old locations so its not a breaking change.
David Pedersen