Bulb-channels

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* Django middleware caching now works on Django 1.11 and Django 2.0.
The previous release only ran on 2.1.

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* Django middleware is now cached rather than instantiated per request
resulting in a significant speed improvement

* ChannelServerLiveTestCase now serves static files again

* Improved error message resulting from bad Origin headers

* runserver logging now goes through the Django logging framework

* Generic consumers can now have non-default channel layers

* Improved error when accessing scope['user'] before it's ready

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* An ALLOWED_ORIGINS value of "*" will now also allow requests without a Host
header at all (especially important for tests)

* The request.path value is now correct in cases when a server has SCRIPT_NAME
set

* Errors that happen inside channel listeners inside a runworker or Worker
class are now raised rather than suppressed

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* AsyncHttpConsumer now has a disconnect() method you can override

* Session and authentication middleware is now non-blocking.

* URL routing context now includes default arguments from the URLconf.

* The FORCE_SCRIPT_NAME setting is now respected in ASGI mode.

* ALLOWED_HOSTS is now set correctly during LiveServerTests.

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* The scope["user"] object is no longer a lazy object, as this conflicts with
any async-based consumers.

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* Async HTTP Consumers and WebSocket Consumers both gained new functionality
(groups, subprotocols, and an async HTTP variant)

* URLRouters now allow nesting

* Async login and logout functions for sessions

* Expiry and groups in the in-memory channel layer

* Improved Live Server test case

* More powerful OriginValidator

* Other small changes and fixes in the full release notes.