Time leakage bug in anime.js when looping animations

Description: Every time an animation loops the excess time is ignored. This leads to "time leakage" which can accumulate over time or cause issues when high delta times occur for a given tick. This can easily be triggered by giving focus to another tab, which causes browsers to reduce or halt the rAF until the user clicks back again.

Real-world case where this bug causes multiple entities with the same looping animations randomly offset from each other to end up synchronized. https://github.com/3DStreet/3dstreet/issues/364

This is a known bug in anime.js (https://github.com/juliangarnier/anime/issues/561) and is also present in A-Frame's fork. Filing this bug here instead for easier discovery in case other people face this issue.

• A-Frame Version: master
• Platform / Device: any
• Reproducible Code Snippet or URL: https://glitch.com/edit/#!/aspiring-honored-dragonfruit