Make MigrationHop MSONable again

[acrutt]

Taking over a previous pull request that was abandoned: #264

[shyuep]

Pls fix the test errors. The linting errors can be dealt with later, but the unittest must pass.

[shyuep]

Pls merge the latest master. A lot of the problems will disappear.

[acrutt]

@shyuep the test I added (pymatgen/analysis/diffusion/tests/test_pathfinder.py::PathfinderTest::test_mhop_msonable) now passes. Are any other changes needed?

[shyuep]

The tests fail because there are changes in your PR with host_symm_structure. These need to be fixed.

[coveralls]

Pull Request Test Coverage Report for Build 2713423963

• 2 of 2 (100.0%) changed or added relevant lines in 1 file are covered.
• 136 unchanged lines in 6 files lost coverage.
• Overall coverage remained the same at 81.363%

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Files with Coverage Reduction	New Missed Lines	%
pymatgen/analysis/diffusion/utils/edge_data_from_sc.py	4	94.81%
pymatgen/analysis/diffusion/utils/supercells.py	4	90.38%
pymatgen/analysis/diffusion/neb/pathfinder.py	10	96.18%
pymatgen/analysis/diffusion/aimd/rdf.py	16	81.91%
pymatgen/analysis/diffusion/neb/full_path_mapper.py	47	81.01%
pymatgen/analysis/diffusion/analyzer.py	55	61.42%

Totals
Change from base Build 2708090438:	0.0%
Covered Lines:	1659
Relevant Lines:	2039

---

💛 - Coveralls

[acrutt]

@shyuep would it be possible to release an updated version of pymatgen-analysis-diffusion with this change on PyPi? I am working on code in emmet that depends on this patch.

[shyuep]

Done.

[acrutt]

Great! Thank you so much @shyuep for your responsiveness in getting this fix addressed in a timely manner.