GitLab

o Added C12 shift term, to match GMX.
o Added tests to compare energies and forces directly to GMX, with and without exclusions.
o Modified set/get LJPME parameters to look similar to electrostatic equivalents.

o Added C12 shift term, to match GMX.
o Added tests to compare energies and forces directly to GMX, with and without exclusions.
o Modified set/get LJPME parameters to look similar to electrostatic equivalents.

Created API and reference implementation of restricting CustomNonbondedForce to selected interaction groups

Platform specific header files get installed.  This allows plugins to be built with just an OpenMM installation, not a full source tree.