Asana tasks!

See https://app.asana.com/0/11724913287040/14477880045173

- improve README.md https://app.asana.com/0/11724913287040/14477880045175
- use `@label@` to label shortcuts, objects and other things in `graph_objs_meta.py` https://app.asana.com/0/11724913287040/14477880045183
- table of content resides `graph_objs_meta-toc.py`

- and more (see commits)
(1) + (2) sounds good to me!

I left 'scl' and 'reversescl' in there to avoid making people change their code to pass API-side validation, but (1) is way better.