Merge pull request #199 from matrix-org/erikj/receipts

synapse/handlers/__init__.py

synapse/handlers/message.py

synapse/handlers/presence.py

synapse/handlers/receipts.py

synapse/handlers/typing.py

synapse/notifier.py

synapse/python_dependencies.py

synapse/rest/client/v2_alpha/__init__.py

synapse/rest/client/v2_alpha/receipts.py

synapse/storage/__init__.py

synapse/storage/_base.py

synapse/storage/receipts.py

synapse/storage/schema/delta/21/receipts.sql

synapse/storage/util/id_generators.py

synapse/streams/events.py

synapse/types.py

tests/handlers/test_typing.py

tests/rest/client/v1/test_events.py

tests/rest/client/v1/test_presence.py