Only build dependent packages as needed

[torch2424]

• Only build libraries that go up it's parent chain on changes
• Introduce chokidar-cli to not run on initial watch
• Parallelized building where I could 😄
• Rust changes are just from building and running the lintes

Why isn't this super fast?

This is because of our options of bundling typescript 😢

• First, I discovered what was causing slower build times was: Compilation very slow with TS v3.4 ezolenko/rollup-plugin-typescript2#148
• So then I tried downgrading typescript in the branch: faster-builds, but only got a very small improvement.
• Then, I tried to avoid the plugin totally, and use babel. But babel did not have a good time transpiling Comlink, and it's build times were also only slightly faster. On the branch: babel-for-typescript
• Lastly, I tried to revert back to Rollup's native watching. But rollup's bundle cache will conflict with rollup-plugin-typescript2's bundle chace, so it does not work 😢 On the branch: rollup-native-watching

Example