test expire session
Merge branch 'develop' into path-33

Conflicts:
	sqlalchemy_mptt/events.py
issue #33
Add level to expire session test
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Merge pull request #37 from bitdeli-chef/master

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Merge branch 'develop' of github.com:ITCase/sqlalchemy_mptt into path-33
Merge branch 'master' of github.com:ITCase/sqlalchemy_mptt into path-33
Flushing the session now expire the instance and it's children fixes #33
Hello 0.1.0 version