Help requiring modules on Espruino-wifi board.

re: ' it appears to me that it doesn't even attempt to look in the modules folder at all according to the console output...'

As I indicated in #4 above, please see #1 at link provide above dated Sun 2018.09.09 for reference to the order of locations looked at by IDE

Thanks for the link to gsap. Learn something new everyday.

'GSAP is a JavaScript library for creating high-performance animations that work in every major browser.'

As it appears that TweenLite wasn't written for Espruino, there may be issues (that might be correctable re-writing parts) straight out of the box. Caveat Emptor

EDIT
Post #6 stepped on during creating this #7 - flip for best reading . . .