Remove LocMapperStore

LMS-2918

@nasthagiri @sarina plz review
Permutation implies reordering, which this isn't doing. Also, would you get an easier to read method by using https://docs.python.org/2/library/itertools.html#itertools.combinations to do something like `org_stop, course_stop = itertools.combinations(range(1, len(parts)), 2)`?