IntersectionObserver & Performance

[markgarity]

As IntersectionObserver becomes standardized and more performant, it would seem smart to utilize that API, and fall-back to the current resize/etc events for browsers that need it.

Currently IntersectionObserver is shipping in Chrome 51+

https://developers.google.com/web/updates/2016/04/intersectionobserver

[thenikso]

wow absolutely! This IntersectionObserver finally addresses what this plugin has been trying to achieve but in a native way.

Definitely worth a look. I hope I can find the time sooner rather than later. Any PR is welcome