* WiP property animations system
* Use better lerp for Angle property animations.
* Fix handling of offset in sprite component.
* Allow animating some sprite layer properties.
* Allow animating some Transform properties.
Obviously not advisable for server entities, but great for client side entities!
* Improve animation property interpolation handling.
Added a "previous" mode.
Made values that cannot be sanely interpolated fall back to this mode.
* Improve some animation docs.
