ImageFap - Fix ImageFap endless scrolling to not load same posts multiple times.
ImageFap - endless scrolling on the Newsfeed page is broken - it often loads the same items multiple time.
The fix is pretty simple - add a "guard condition" to handle the fact that the loading of new items is asynchronous. In this case, simply check if the same timestamp for which new items are to be fetched has been used before, already.
This script neither does nor fixes anything else (for example: ImageFap's endless scrolling feature has additional issues like not honoring the selected categories status, galleries and comments).
Tested on Firefox with both TamperMonkey and GreaseMonkey.
The script is presented AS-IS with no guarantees - feedback is welcome.
