Merge branch 'master' into sketch-map

.travis.yml

CHANGES/v2.1.txt

CHANGES/v2.2.txt

CHANGES/v2.3.txt

CHANGES/v2.4.txt

Makefile

README

developer-doc/AddingAMeasure.txt

developer-doc/AddingAMultColvar.txt

patches/gromacs-2016.1.config

patches/gromacs-2016.1.diff/src/gromacs/CMakeLists.txt

.../gromacs-2016.1.diff/src/gromacs/CMakeLists.txt.preplumed

patches/gromacs-2016.1.diff/src/gromacs/mdlib/force.cpp

...gromacs-2016.1.diff/src/gromacs/mdlib/force.cpp.preplumed

patches/gromacs-2016.1.diff/src/gromacs/mdlib/minimize.cpp

...macs-2016.1.diff/src/gromacs/mdlib/minimize.cpp.preplumed

patches/gromacs-2016.1.diff/src/programs/mdrun/md.cpp

...s/gromacs-2016.1.diff/src/programs/mdrun/md.cpp.preplumed

patches/gromacs-2016.1.diff/src/programs/mdrun/mdrun.cpp

...romacs-2016.1.diff/src/programs/mdrun/mdrun.cpp.preplumed