Add support for mpirun named "srun"

Change-Id: Ib271261052f6cbee3c58c783592dbea0c6277470
Added a basic test for each of the 12 enforced rotation potentials.

Reference values generated with code version Icc6c7fceaba3fa53...,
however, the values for the forces, energies, and torques are
(at least for the double precision cases) identical to the analytical
results, which are found in the README file in the rotation subdirectory.

Change-Id: Iabc7f56ddee0de46162fb540241c42ceed130bd6