initial addition of validation files
refactor some config setup out of mgdb so it can be shared with mgvv. Numerous small improvements in mgvv and matgendb.vv modules.
Adding unit tests
Better DB error defaults. Tolerate only 1, skip output automatically on empty report.
fix added exists for inequality
Merge branch 'master' of https://github.com/materialsproject/pymatgen-db

Conflicts:
	scripts/mgdb
Merged in shyue's changes, I think it will all still work?