Roll

- **Breaking change**:
* `request` event is now sent *after* the URL matching and the HTTP verb check,
please use the new `headers` event for these use cases.
- Added new `headers` event, to hook after request headers have been read, but
before the request body has been consumed. ([227](https://github.com/pyrates/roll/pull/227))
- Added method `Request.read()` to load and consume request body in one call

- Python 3.9 support

- Added `credentials` parameter to `cors` extension, to deal with `Access-Control-Allow-Credentials` header
([155](https://github.com/pyrates/roll/pull/155))

- Fixed URL quoting in testing utility ([149](https://github.com/pyrates/roll/pull/149), [#150](https://github.com/pyrates/roll/pull/150))

- Fixed request not properly drained in case of error ([138](https://github.com/pyrates/roll/pull/138))
- Moved `app.url_for` helper to a dedicated extension: `named_url` ([143](https://github.com/pyrates/roll/pull/143))
- Added `request.referrer` and `request.origin` shortcuts ([147](https://github.com/pyrates/roll/pull/147))

- Added `app.url_for` helper ([136](https://github.com/pyrates/roll/pull/136))
- Added `response.redirect` shortcut ([134](https://github.com/pyrates/roll/pull/134))
- Fixed URL not quoted in testing utility
- Added `default_index` to `static` extension ([95](https://github.com/pyrates/roll/pull/95))
- Added support for streamed responses ([89](https://github.com/pyrates/roll/pull/89))
- Added support for async reading of request body ([89](https://github.com/pyrates/roll/pull/89))
- `Request.json` is now cached ([90](https://github.com/pyrates/roll/pull/90))