Merge release-5-0 into release-5-1

Merge release-5-0 into release-5-1

Conflicts:
	cmake/gmxManageFFTLibraries.cmake
Fixes from release-5-0 goes in only one branch of the refactoring in
release-5-1 that separate the own-fftw build from an installed-fftw
build.

	docs/manual/monster.bib
Insertions in both branches, both retained

	src/gromacs/gmxana/gmx_wham.cpp
Fixed formatting of copyrighted years.

	src/programs/mdrun/mdrun.cpp
Relocation of please_cite() calls was adjacent to removal of bSepPot,
trivial resolution

Change-Id: I9d6116534775906d74ddbd45925176a21b5afcd9