Created files for AMOEBA 2013 force field
Added documentation and header information for AMOEBA 2013 force field
Fixed a bug in a test case
Merge pull request #440 from peastman/master

Fixed a bug in a test case
AmoebaTorsionTorsionForce can calculate derivatives of the grid points automatically
Fixed incorrect specification of torsion-torsion terms in AMOEBA 2013 force field
Fixed typo in modeller docstring.
Python 3 compatibility
Merge pull request #444 from mpharrigan/py34

Python 3 compatibility
Merge pull request #442 from kyleabeauchamp/tinydocfix

Fixed typo in modeller docstring.
Regenerated AMOEBA 2013 force field based on corrected parameter file
Merge branch 'amoeba' of https://github.com/peastman/openmm into peastman-amoeba
Merge branch 'peastman-amoeba'
Merge pull request #455 from peastman/master

Implemented AMOEBA 2013 force field
Fixed incorrect units in AmoebaStretchBendForce.getStretchBendParameters()
Merge pull request #457 from peastman/master

Fixed incorrect units in AmoebaStretchBendForce.getStretchBendParameters()