Merge pull request #54 from jchodera/master

Unifying tests for pymbar-2.1
Make import styles in init consistent.
Removing the old test - either automated or moved to examples.
Merge pull request #57 from choderalab/init

Make import styles in init consistent.
Changed a warning in BAR to an error + added handling

Overflow in the solution to the BAR equations is now
caught so we can handle it explicitly.
Ran autopep8 and deleted old GPL file.
Merge pull request #61 from choderalab/pep8_2

 Ran autopep8 and deleted old GPL file.