Merge pull request #582 from matrix-org/erikj/presence

synapse/api/constants.py

synapse/handlers/events.py

synapse/handlers/message.py

synapse/handlers/presence.py

synapse/handlers/profile.py

synapse/handlers/sync.py

synapse/rest/client/v1/presence.py

synapse/rest/client/v1/room.py

synapse/rest/client/v2_alpha/receipts.py

synapse/rest/client/v2_alpha/sync.py

synapse/storage/__init__.py

synapse/storage/account_data.py

synapse/storage/events.py

synapse/storage/prepare_database.py

synapse/storage/presence.py

synapse/storage/receipts.py

synapse/storage/schema/delta/30/presence_stream.sql

synapse/storage/stream.py

synapse/storage/tags.py

synapse/storage/util/id_generators.py