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From @peastman:

> Test cases are failing. I believe it's because the parent for a ScaledUnit needs to be a Unit, not another ScaledUnit. So in the line
>
> ```
>  hartree_base_unit = ScaledUnit(4.3597447222071e-18, joule_base_unit, "hartree", "Ha")
> ```
>
> replace joule_base_unit with joule.

This is of immediate need to QCEngine, in particular MolSSI/QCEngine#151

Use correct parameters for nucleic acids with GBn2

Barostats use checkpointed random number generator

Support all values of NBXMod in CHARMM parameter files

Minor code cleanup to reference platform

Fixed compilation error introduced by #2378

Added the W-H combining rule for AMOEBA+ VdW

Added max step size option to variable step size integrators

Add Softcore support to AmoebaVdwForce.

Enable docker for GPU builds

Improve the performance of sending the AmoebaVdwLambda to Cuda using pinned host memory; Updated the AmoebaVdwForceProxy to version 3, and added backward compatibility to version 2; updated TestAPIUnits.py to handle the per particle lambda flag