GitLab

Restructured how force and energy computations are done to make it easier to write plugins for the CUDA platform

The differences in the Ewald energies between the Reference and Cuda platforms were traced to roundoff error in the 
computation of the Vdw and Coulomb ixns for the short-range energy contribution (verified using double precision in the sum); the vdw and Coulomb terms are now accumulated separately and then added to the total energy 

In Ewald SR portion of code, the LJ contribution to dEdR was missing a factor of (inverseR*inverseR)

All energies existing in Preview Release 3 now run on the GPU, new Ewald energy terms still use Reference implementation

Forced computation of dot product used in computing angles to be done in double precision; acos() is very steep for angles near pi and single precison was giving disagreement w/ corresponding Gromacs values (discrepancies of the order of ~1.0)