Fork of https://github.com/VernierST/godirect-js, with some changes.

• Various bugfixes and consistency improvements.
• Switched to TypeScript.
• Refactored to async/await in a lot of places.

I made this for my own use and don't intend to contribute the changes upstream since the upstream repo seems pretty dead and I'm not sure if Vernier wants my changes. But feel free to incorporate anything you'd like!

Published to @calebeby/godirect.