#19 Update ProtoMol to support new OpenMM

[Anonymous]

To support the new version of OpenMM, two changes are needed:

1) Scons libprotomol-config.py needs to be updated to used the new name of the OpenMM library file

2) OpenMM now supports cut offs for GB. We need to call the appropriate method on the GB force object to set the cut offs in case the defaults change.