Merge branch 'release-v0.9.2'

CHANGES.rst

contrib/systemd/log_config.yaml

synapse/__init__.py

synapse/app/homeserver.py

synapse/config/captcha.py

synapse/config/registration.py

synapse/config/server.py

synapse/events/__init__.py

synapse/federation/federation_base.py

synapse/federation/transport/server.py

synapse/handlers/_base.py

synapse/handlers/auth.py

synapse/handlers/federation.py

synapse/http/client.py

synapse/http/matrixfederationclient.py

synapse/http/server.py

synapse/push/__init__.py

synapse/python_dependencies.py

synapse/rest/client/v1/__init__.py

synapse/rest/client/v2_alpha/__init__.py