Add an efactor parameter to adjust epsilon values

[chrisjonesBSU]

This PR lets us adjust the epsilon values from the forcefield on the fly using an e_factor parameter in the Simulation class. The epsilon values are adjusted directly in the hoomd.md.pair.LJ parameter dictionary.

[codecov[bot]]

Codecov Report

Merging #105 (415e6f0) into master (2258c67) will increase coverage by 0.11%. The diff coverage is 100.00%.

Additional details and impacted files

[](https://codecov.io/gh/cmelab/polybinder/pull/105?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cmelab) ```diff @@ Coverage Diff @@ ## master #105 +/- ## ========================================== + Coverage 90.75% 90.86% +0.11% ========================================== Files 7 7 Lines 822 832 +10 ========================================== + Hits 746 756 +10 Misses 76 76 ``` | [Impacted Files](https://codecov.io/gh/cmelab/polybinder/pull/105?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cmelab) | Coverage Δ | | |---|---|---| | [polybinder/simulate.py](https://codecov.io/gh/cmelab/polybinder/pull/105?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cmelab#diff-cG9seWJpbmRlci9zaW11bGF0ZS5weQ==) | `87.65% <100.00%> (+0.39%)` | :arrow_up: |

[RainierBarrett]

LGTM