use a softer transition for the install overlay

[johanneseckert]

When using the install a home screen overlay, you use spring curves to display it.
When a prototype is loading, it can cause the browser to drop a few frames while generating the views, and that will make spring curves with requestAnimationFrame go crazy, you will see the overlay wiggle around with almost no friction and a lot of tension.

Maybe you can switch to a bezier curve or even linear, just to make sure its not irratic?

[tisho]

I think the real issue here is that dropping frames from a spring-based animation makes it go crazy :) I'll see if I can fix it. Thanks for reporting.