Add abstract AnimationSequence API that both animated entity and scene model can use Implement AnimationSequence for scene model Add animation picker to assetpreview to test API (if we want to keep it) https://files.facepunch.com/layla/1b1411b1/sbox_uS7rxaNYTg.mp4 Revert test TypeForwardedTo AnimationSequence (hopefully fix managed test failing)