sample gmxapi MD plugins for GROMACS 2019

Compatibility updates and bug fixes for gmxapi 0.0.7 and GROMACS 2019.

sample gmxapi MD plugins for 0.0.7

Summary of changes for 0.0.7:

• updates for compatibility with GROMACS 2019 (see kassonlab/gmxapi#157)
• updates to building and linking
• updates to continuous integration testing on Travis-CI
• update pybind11 to 2.2.4
• embed googletest source so that automatic download is no longer default

Note: If updating plugin code from gmxapi 0.0.6:
For details on the plugin code updates for GROMACS 2019 and gmxapi 0.0.7, refer to commit a9f3633

gmxapi sample_restraint 0.0.6

Sample restraint plugin code for GROMACS using gmxapi 0.0.6.

Bug fixes and stability improvements, build system improvements, documentation improvements

Refer to patches of individual source files for ideas on updating custom plugin code.

• ensemblepotential.h
• ensemblepotential.cpp
• export_plugin.cpp
• src/cpp/CMakeLists.txt
• src/pythonmodule/CMakeLists.txt

Refer to https://github.com/kassonlab/sample_restraint , https://github.com/kassonlab/gmxapi and
https://doi.org/10.1093/bioinformatics/bty484 for more details.

gmxapi sample_restraint 0.0.5

First versioned release of the gmxapi sample restraint plugin repository.

Establishes synchronization between the versioned releases and master branches of the three repositories.