- Scroll is identified by line index and layout index, instead of just
layout index
- Shaping has the option to prune, where caches outside of the scroll
view are cleared
- Syntax editor no longer requires layout of all lines, only of lines
inside scroll
- BufferLine has a metadata field that can be used by other abstractions
to know when text was changed
Add tests that will match rendered words/paragraphs against reference
images.
Use env var `GENERATE_IMAGES` to write the initial reference images to
the repository.
