sqlalchemy/orm, sqlalchemy/event, sqlalchemy/testing

Conflicts:
	lib/sqlalchemy/dialects/mssql/base.py
	lib/sqlalchemy/dialects/mysql/base.py
	lib/sqlalchemy/dialects/mysql/mysqldb.py
	lib/sqlalchemy/dialects/oracle/base.py
	lib/sqlalchemy/dialects/sybase/base.py
	lib/sqlalchemy/orm/attributes.py
	lib/sqlalchemy/orm/evaluator.py
	lib/sqlalchemy/orm/identity.py
	lib/sqlalchemy/orm/instrumentation.py
	lib/sqlalchemy/orm/loading.py
	lib/sqlalchemy/orm/mapper.py
	lib/sqlalchemy/orm/session.py
	lib/sqlalchemy/orm/sync.py
	lib/sqlalchemy/sql/compiler.py
	lib/sqlalchemy/sql/selectable.py
	lib/sqlalchemy/testing/requirements.py
	lib/sqlalchemy/testing/suite/test_select.py

  to get all flake8 passing

- other cleanup
- don't need compat.decimal, that approach never panned out. hopefully
outside libs aren't pulling it in, they shouldn't be