* BaseClient and AsyncClient
* Introduce 'httpx.Client'
* Top level API -> sync
* Top level API -> sync
* Add WSGI support, drop deprecated imports
* Wire up timeouts to urllib3
* Wire up pool_limits
* Add urllib3 proxy support
* Pull #734 into sync Client
* Update AsyncClient docstring
* Simpler WSGI implementation
* Set body=None when no content
* Wrap urllib3 connection/read exceptions
* Drop nox in favor of vanilla scripts
* Use named stages
* Fix attrs dependency resolution madness
* Add missing mkautodoc dev dependency
* Add missing install step on windows build
* Explicitly define stage order so that timed out Windows build runs last
* Add missing dev dependency on Black
* Clean up contributing guide
* Separate docs into docs-build and docs-serve