Script to sort ROBOT template by hierarchy

[jamesaoverton]

ROBOT templates are often used to represent a full branch of an ontology, e.g. OBI's epitope-assays.tsv. We usually sort these tables by ID.

I want to be able to sort them into tree order. This would keep similar classes closer together, making it easier to see shared modelling patterns.

OBI's convention is to assert single inheritance, so the 'Parent' column will have a single label value. For tables representing branches, there should be no gaps in the tree. Siblings should be sorted alphabetically. (Natural number sort would be even better.)

It might also be nice to indent the label column by tree depth.