Expand unit test coverage

[kneitinger]

Goal

At least 80% test coverage in repo.

Tasks

• [ ] nightsketch_derive macro internals
• [x] #19
• [ ] nightsketch features (testing clap derivations, etc)
• [ ] nightgraphics geometry/canvas/render coverage improvement
• [ ] nightgraph-ui custom components (sketch loading, parameter control generation, etc)

Note

I don't believe sketches themselves make sense to include in this figure