Merge branch 'develop' into markjh/config_cleanup

synapse/app/homeserver.py

synapse/config/captcha.py

synapse/handlers/identity.py

synapse/handlers/message.py

synapse/handlers/presence.py

synapse/http/server.py

synapse/push/pusherpool.py

synapse/storage/appservice.py

synapse/storage/keys.py

synapse/storage/pusher.py

synapse/storage/registration.py

synapse/storage/room.py

synapse/storage/roommember.py

synapse/storage/schema/delta/17/user_threepids.sql

synapse/storage/state.py

synapse/storage/util/id_generators.py