Fixed issue where .revert() was unable to correctly abort the RAF loop

I'm using **jquery-seeThru** on a (single) video that is dynamically added and removed from the page. As the video is added and removed, I've noticed a huge slowdown in performance.

I tracked the issue to `.revert()` not being able to access the current RAF interval loop from `$this.data('seeThru')` and therefor not correctly clearing the loop.

This is because the RAF `interval` created in `drawFrame()` is not being stored against `$this.data('seeThru')`.

I've built and checked this change against the test, but have only committed the change to the source JS.