Added tests for PT and HE sanity check.
Updated docstring on HE sanity check.
Changed states to thermodynamic_states for clarity.
Updated HE, PT, RE, and minor tests.
Cleaned up some extra commented out code.
Cleared one more comment
Changed the comment style on block comment for clarity in the diff.
First checkin of general MCMC move approach.
Fixed minimize docstring in mcmc.py
Added NAN detection helper function to mcmc.py, also general cleanup.
Minor cleanup.
Updates
Minor cleaning up in test
Load in system from the thermodynamic state before MCMCSampler.run()
Fixed pressure issue.
Merge pull request #51 from choderalab/fullmcmc

[WIP] Full MCMC support