Merge "Use context managers for threading.Lock()"

diff --cc lib/sqlalchemy/ext/automap.py
Simple merge

diff --cc lib/sqlalchemy/ext/declarative/base.py
Simple merge

diff --cc lib/sqlalchemy/orm/__init__.py
Simple merge

diff --cc lib/sqlalchemy/orm/mapper.py
Simple merge

diff --cc lib/sqlalchemy/pool/dbapi_proxy.py
Simple merge

diff --cc lib/sqlalchemy/util/langhelpers.py
Simple merge

diff --cc lib/sqlalchemy/util/queue.py
Simple merge