Merge branch 'master' of https://github.com/plumed/plumed2

.travis.yml

.travis/install.cppcheck

.travis/install.doxygen

.travis/install.gawk

.travis/install.xdrfile

CHANGES/v2.3.txt

CHANGES/v2.4.txt

README

configure

configure.ac

developer-doc/HowToContributeToPlumed.txt

developer-doc/plmdIntro.txt

patches/gromacs-2016.3.config

patches/gromacs-2016.3.diff/src/gromacs/CMakeLists.txt

.../gromacs-2016.3.diff/src/gromacs/CMakeLists.txt.preplumed

patches/gromacs-2016.3.diff/src/gromacs/mdlib/force.cpp

...gromacs-2016.3.diff/src/gromacs/mdlib/force.cpp.preplumed

patches/gromacs-2016.3.diff/src/gromacs/mdlib/minimize.cpp

...macs-2016.3.diff/src/gromacs/mdlib/minimize.cpp.preplumed

patches/gromacs-2016.3.diff/src/programs/mdrun/md.cpp