Removing state pollution in idd_commlst

[sturmianseq]

This PR aims to improve test reliability of test test_group2commlst by removing state pollution in idd_commlst by making a deepcopy

The test can fail in this way by running pip3 install pytest-repeat; python3 -m pytest --count=2 $test_path:

        for (groupcommlst,) in data:
            glist = iddgroups.iddtxt2grouplist(iddtxt)
            result = iddgroups.group2commlst(idd_commlst, glist)
>           assert result == groupcommlst
E           AssertionError: assert [[['group Non...t 7.0']], ...] == [[['group Non...t 7.0']], ...]
E             At index 0 diff: [['group None', 'idfobj Lead Input', 'group None', 'idfobj Lead Input']] != [['group None', 'idfobj Lead Input']]
E             Full diff:
E               [
E                [['group None',
E             +    'idfobj Lead Input',
E             +    'group None',
E                  'idfobj Lead Input']],...
E             
E             ...Full output truncated (60 lines hidden), use '-vv' to show

It may be better to clean state pollutions so that some other tests won't fail in the future due to the shared state pollution.