- Update execa to v0.8
- Add JSDoc documentation for everything
- Fix being unable to pass boolean to `shell` option due to intersection type issues
- Restructure definitions file based on chroma-js typings to expose function return types
These weak type errors were not caught in TS 2.4 RC. The final TS 2.4
will catch weak type errors with primitives, so this PR fixes those
now-caught errors.