Merge pull request #13 from matrix-org/request_logging

synapse/app/homeserver.py

synapse/config/logger.py

synapse/crypto/keyclient.py

synapse/http/client.py

synapse/http/server.py

synapse/storage/_base.py

synapse/util/async.py

synapse/util/logcontext.py

synapse/util/logutils.py

tests/util/test_log_context.py