Fuzzier Mark Generation

[thehabes]

When creating Mark objects (to highlight selected text for a given source) we rely on strict fragment selector indexes or exact text match. There are plenty of scenarios that will screw up this UI, such as if the source text itself changes. Improve the Marking system to accommodate small inaccuracies or content fluctuation.

[thehabes]

In particular, attempt to handle this when the text content of a T-PEN line changes.

The text content of my line is "to whom it may concern". In the Gallery of Glosses, I highlight "to whom it may concern" and attach it to a Gloss. Now this text appear highlighted yellow when this project is loaded. Then, in T-PEN, I realize the text is wrong. I update the text of the line to be "I write to whom it may concern". Now when this transcription loads in the Gallery of Glosses, "I write to whom it ma" is highlighted instead of "to whom it may concern".