Tools: add functionality to run different code version (serial, OpenMP, MPI, MPI+GPU). Update sPuReMD control file parser to ignore non-shared memory parameters.

Tools: update run_sim.py to work with absolute paths (by refereing supplied executable path). Begin updating testing scripts.

sPuReMD: backport changes for reax_list, struct declaration/definition separation, interaction_function.

sPuReMD: separate total energy computation and fix Python driver bug with structure definition for ctypes. Allow disabling file logging during simulation.

sPuReMD: refactor tri solve level sched memory management. Change OpenMP thread scheduling policy to static. Modify logging output format.

sPuReMD: fix diagonal preconditioner computation and level scheduling application. Modify preconditioner logic to compute and cache sparsity-based info. Update run script.