Minor tweaks

Merge pull request #25 from wehs7661/hist_correction

Implement the method for histogram correction

Merge pull request #23 from wehs7661/fix_poor_sampling

Resolve the issue of poor sampling

Merge pull request #9 from wehs7661/remove_gmxapi

Remove the use of gmxapi

Implemented the method of exhaustive swaps

Refined setup.py to get ready for deployment on PyPI; Modified README

Modified test_ensemble_EEXE.py to test CI

Implemented the new weight-combining method (using probability ratios…

…) and removed the old ones

Tried to pass CI