Verify / reproduce Argon results from MDMC Fortran version

Results from using the deprecated MDMC (Fortran) code on Argon data was reported in

[RAL-TR-2017-014 (14).pdf](https://github.com/MDMCproject/MDMCv0.2_pilot/files/6592294/RAL-TR-2017-014.14.pdf)

I think we are now ready to verify the results in the above technical report. In particular, in this issue, refine the LJ epsilon and sigma FF parameters against the van Well data. Where as starting values pick e=1.5K/mol and s=4.0Å and then let both these FF parameters be refined, and observe how these refine towards the published values: e=1.0243K/mol and s=3.36Å (van Well et al., 1985).

This issue here is to report on results from doing the above, and discuss and understand any differences observed.