Merge pull request #621 from matrix-org/daniel/ratelimiting

synapse/handlers/_base.py

synapse/handlers/directory.py

synapse/handlers/federation.py

synapse/handlers/message.py

synapse/handlers/profile.py

synapse/handlers/room.py

synapse/rest/client/v1/directory.py

synapse/rest/client/v1/profile.py

synapse/rest/client/v1/room.py

tests/handlers/test_profile.py

tests/replication/test_resource.py

tests/rest/client/v1/test_profile.py

tests/utils.py