Merge branch 'develop' into babolivier/mark_unread

.buildkite/docker-compose.py35.pg95.yaml

.buildkite/docker-compose.py37.pg11.yaml

.buildkite/docker-compose.py37.pg95.yaml

.buildkite/merge_base_branch.sh

.buildkite/postgres-config.yaml

.buildkite/scripts/create_postgres_db.py

.buildkite/scripts/test_old_deps.sh

.buildkite/scripts/test_synapse_port_db.sh

.buildkite/sqlite-config.yaml

.buildkite/test_db.db

.buildkite/worker-blacklist

.github/ISSUE_TEMPLATE.md

.github/ISSUE_TEMPLATE/BUG_REPORT.md

.github/PULL_REQUEST_TEMPLATE.md

.gitignore

AUTHORS.rst

CHANGES.md

CONTRIBUTING.md

CONTRIBUTING.rst

INSTALL.md