PG-PuReMD: fix error due to function prototype change. PuReMD: fix issues with GCC new inline behavior, fix reax_list bugs. sPuReMD: change exit code to zero.

PG-PuReMD: complete memory changes. Remove max register per CUDA function option in build. Other misc. changes.

Just removing now unnecessary printfs that clutter the code

The MPI-Not-GPU version is able to run through all benchmarks with decent agreement with the other versions now. The test harness has been modified to allow testing between the three functional versions.
Also added a README file in the test_harness directory about how to use the harness. Finally, I have saved one copy of the output from the previous test run to sim_output_082516.txt, for future comparison.

Add minor checks to PG-PuReMD and PuReMD. Major refactoring of sPuReMD: backport much of PuReMD code and add CUSTOM geo format.