Merge branch 'v2.5' into v2.5-conda

.travis.yml

CHANGES/v2.0.md

CHANGES/v2.1.md

CHANGES/v2.2.md

CHANGES/v2.3.md

CHANGES/v2.4.md

CHANGES/v2.5.md

README.md

VERSION

patches/gromacs-2018.5.config

patches/gromacs-2018.5.diff/src/gromacs/CMakeLists.txt

.../gromacs-2018.5.diff/src/gromacs/CMakeLists.txt.preplumed

patches/gromacs-2018.5.diff/src/gromacs/mdlib/force.cpp

...gromacs-2018.5.diff/src/gromacs/mdlib/force.cpp.preplumed

patches/gromacs-2018.5.diff/src/gromacs/mdlib/minimize.cpp

...macs-2018.5.diff/src/gromacs/mdlib/minimize.cpp.preplumed

patches/gromacs-2018.5.diff/src/programs/mdrun/md.cpp

...s/gromacs-2018.5.diff/src/programs/mdrun/md.cpp.preplumed

patches/gromacs-2018.5.diff/src/programs/mdrun/mdrun.cpp

...romacs-2018.5.diff/src/programs/mdrun/mdrun.cpp.preplumed