Thanks for sharing this out there. As someone who became an accidental Flash guy (and at that, more of the 'timeline only' set), I'm using this as a way to jump into HTML5 banner development using GSAP and coding -- and do it the 'right' way. I finally got it set up on Mac OS X 10.11 El Capitan (which turned out to be no small feat). And so far it's working great.
I see that you've made some moves towards adding banner sizes in there. That's great, too.
Well, just wanted to say hi -- and that I'm using it, and it's a great tool.