List Editing Design

Design notes for #674 and future list editing work.

- [ ] Add more examples for how operations work to solve list editing actions
- [ ] Add collab examples
I had to do some explaining about things like this on the ML some time back. Perhaps there are some good/bad practices in there that are of some help? https://open.nlnet.nl/pipermail/webodf/2013-September/000072.html