composite line numbering in tragedy

[lcerrato]

Originated here: https://github.com/PerseusDL/canonical-greekLit/issues/158

I believe the question deals with something like this:

where the lines between 530-536 (ff) are rendered in various ways (if they are assigned specific line numbers at all).

Based on the presumption that the CTS lines are arbitrary containers, I would propose something like this:

which uses the variants to identify the line numbers the editors have kept, so to speak. From there, I choose to omit a number.

Again, this is based on the presumption that the containers are arbitrary to begin with, and that I want to keep some relationship with the print work for ease of later corrections.

Another solution would be sequential numbering with old line numbers converted to milestones for the purpose of maintaining the print relationship.

[lcerrato]

Note this work was informed by https://github.com/PerseusDL/canonical-greekLit/pull/129