Documentation build updates

Fix python/move

USER-DPD: External State RNG

Update the Kokkos library in LAMMPS to v2.5.00

This reverts commit 4a3a6b44.
As it turns out, when using the LAMMPS python wrapper from inside
code using the PYTHON package, the library symbols *are* needed.
Thanks for Richard Berger (@rbberger) for pointing this out.

This reverts commit 4d915dba.

This reverts commit 4a3a6b44.
As it turns out, when using the LAMMPS python wrapper from inside
code using the PYTHON package, the library symbols *are* needed.
Thanks for Richard Berger (@rbberger) for pointing this out.

the sphinxcontrib.image extension was broken with sphinx 16.x.
however, sphinx 15.x breaks with newer version of the multiprocessor module.
so we suspend the thumbnail processing and lift the lock to sphinx 15.x

also, the number of parallel sphinx tasks is can be overridden with SPHINXEXTRA="-j #'.
default is to try use all local CPU cores.

Fix compile error in pair_yukawa_kokkos

PyLammps bugfix to support custom thermo output with vector element addressing

Reduce Kokkos compile dependencies

Improve ReaxFF

Collected bugfixes and small updates for next patch

Add ExTeP pair style

Added a KOKKOS-enabled Yukawa pair style.

new example scripts for fix gcmc

Add pair_yukawa_kokkos to Install.sh and minor cleanup.

These changes look fine. Sorry for the tabs, I must have forgotten about those.

This is to avoid confusion to what LAMMPS considers to be an
integrator like Verlet and RESPA.

Removing the loop over atoms by using NumPy array indexing allows to recover
performance close to that of plain fix nve.