preped read expected levels to be called externally
Merge branch 'master' of https://github.com/f4hy/effectivemass
checks duplicates
have expected levels work for just 'E'
flake8 agreement
refactor and show how many states below
allow momentum_permute to support other output formats
make momentum permute return the momenta in a list, unjoined strings
output all irrep rows and momenta permutations