bugfix in SampleTrajectory.py
Merge pull request #435 from SimTk/sample_bug

bugfix in SampleTrajectory.py
Use LooseVersion so setup works with dev version of mdtraj
Merge pull request #439 from mpharrigan/looseversion

Use LooseVersion so setup works with dev version of mdtraj
Merge branch 'master' of github.com:schwancr/msmbuilder into shukla