David Wilkins

Before vdiffr began using testthat's file snapshot mechanism, when a new `expect_doppelganger()` expectation was added it would have to be inspected and accepted with `manage_cases()` before the test would pass....

Implement the [Synthetic Biology Open Standard](https://sbolstandard.org) (SBOL) [sequence feature glyphs](https://sbolstandard.org/visual-glyphs/). The current rough plan for this is: - Add a `geom_()` function for each sequence feature glyph - `geom_gene_arrow()` becomes...