Merge pull request #12 from matrix-org/federation_authorization

demo/start.sh

docs/server-server/signing.rst

scripts/check_event_hash.py

scripts/check_signature.py

scripts/hash_history.py

synapse/api/auth.py

synapse/api/errors.py

synapse/api/events/__init__.py

synapse/api/events/factory.py

synapse/api/events/room.py

synapse/api/events/utils.py

synapse/api/events/validator.py

synapse/app/homeserver.py

synapse/config/server.py

synapse/crypto/event_signing.py

synapse/federation/pdu_codec.py

synapse/federation/persistence.py

synapse/federation/replication.py

synapse/federation/transport.py

synapse/federation/units.py