GitLab

* Created API for HIPPO force field

* Beginning of reference implementation of HIPPO

* Continuing reference implementation of HIPPO

* Continuing reference implementation of HIPPO

* Continuing reference implementation of HIPPO

* Continuing reference implementation of HIPPO

* Continuing reference implementation of HIPPO

* Continuing reference implementation of HIPPO

* Continuing reference implementation of HIPPO

* Completed reference of HIPPO with no cutoff

* Beginning cutoffs/PME for reference implementation of HIPPO

* Continuing PME for reference implementation of HIPPO

* Continuing PME for reference implementation of HIPPO

* Continuing PME for reference implementation of HIPPO

* Completed reference implementation of HIPPO

* Cleanup and optimization to HIPPO reference

* Further cleanup to HIPPO

* Combined direct space interactions into a single loop

* Compute direct space interactions in quasi-internal frame

* Beginning of CUDA implementation of HIPPO

* Continuing CUDA implementation of HIPPO

* Continuing CUDA implementation of HIPPO

* Continuing CUDA implementation of HIPPO

* Continuing CUDA implementation of HIPPO

* Continuing CUDA implementation of HIPPO

* Continuing CUDA implementation of HIPPO

* Continuing CUDA implementation of HIPPO

* Continuing CUDA implementation of HIPPO

* Continuing CUDA implementation of HIPPO

* Continuing CUDA implementation of HIPPO

* Continuing CUDA implementation of HIPPO

* Continuing CUDA implementation of HIPPO

* Continuing CUDA implementation of HIPPO

* Finished CUDA implementation of HIPPO

* More features and test cases for HippoNonbondedForce

* Serialization and Python API for HippoNonbondedForce

* Fixed sign error in computing forces

of just 1.  Backwards compatibility is provided by making the 2nd force constant
default to -1, which is reinterpreted as "copy the first force constant".

Updates both the reference and CUDA kernels.