Starting with:
Included Tone.js
as a subtree, using the following command (via http://blogs.atlassian.com/2013/05/alternatives-to-git-submodule-git-subtree/):
git subtree add --prefix src/script/lib/tone.js https://github.com/TONEnoTONE/Tone.js.git master --squash
If we need to update Tone.js
in the future we can use the following command.
git subtree pull --prefix src/script/lib/tone.js https://github.com/TONEnoTONE/Tone.js.git master --squash