Merge branch 'release-v0.9.3' of github.com:matrix-org/synapse

AUTHORS.rst

CHANGES.rst

synapse/__init__.py

synapse/api/auth.py

synapse/app/homeserver.py

synapse/config/_base.py

synapse/config/captcha.py

synapse/config/metrics.py

synapse/config/repository.py

synapse/config/server.py

synapse/federation/transport/server.py

synapse/handlers/appservice.py

synapse/handlers/message.py

synapse/handlers/presence.py

synapse/http/client.py

synapse/http/matrixfederationclient.py

synapse/http/server.py

synapse/notifier.py

synapse/rest/client/v1/transactions.py

synapse/server.py