Merge branch 'master' into add-user-reaxc-omp

doc/Makefile

doc/src/compute_saed.txt

doc/src/compute_sna_atom.txt

doc/src/dihedral_spherical.txt

doc/src/fix_gle.txt

doc/src/fix_langevin_drude.txt

doc/src/manifolds.txt

doc/src/package.txt

doc/src/pair_morse.txt

doc/src/pair_python.txt

doc/src/pair_snap.txt

doc/src/pair_zero.txt

doc/src/tutorial_pylammps.txt

examples/COUPLE/simple/simple.cpp

examples/snap/Ta06A.snapparam

examples/snap/W_2940_2017_2.snap

examples/snap/W_2940_2017_2.snapparam

examples/snap/W_2940_2017_2_He_JW2013.snap

src/GRANULAR/pair_gran_hooke_history.cpp

src/KSPACE/pppm.cpp