Fix/cant see shaders code

[vulongphan]

Fixes #1595

I have verified that this pull request:

• has no linting errors (npm run lint)
• is from a uniquely-named feature branch and has been rebased on top of the latest develop branch. (If I was asked to make more changes, I have made sure to rebase onto develop then too)
• is descriptively named and links to an issue number, i.e. Fixes #123

[catarak]

Thank you for working on this! It's working for me. I know that the code in this script is a little messy, but would it be possible for you to put the new code you added into a separate function? I think eventually it would make sense to clean up this file, but for now, when adding new code, I think it makes sense to add it in as cleanly as possible.

[vulongphan]

Yes, it makes sense to me too. I have moved all my added code to addAssetsToProject(). Could you please have a look?

[catarak]

Thanks for making that change! Looks good to me.

[catarak]

This is working great for me. I think the next important step here is refactoring this file so that it just uses async/await—there are callbacks, promises, and async/await here and it's kind of a mess :) I'll open a new issue!