Bug/stud 1962

@cahrens please review

@nasthagiri managing version conflict errors while keeping them when we need them may require another context manager or some other mechanism. (see all of the for_version stuff in the new test code)
Yes, split has version guids on retrieved items whereas draft doesn't. split doesn't use the `is_draft` hidden attribute (we should really get rid of that or change it into a function or something better than sometimes it's here, sometimes it's not.)