1.8.3

- Improved autoCSS property detection so that if the target is a DOM element, custom properties will be honored rather than being interpreted as css-related values.

- Fixed an issue in the timeline classes that could create an infinite loop in a very rare scenario. And now when a timeline has tweens with negative startTimes, it will shift all children forward (until there are no negative startTimes) and if the parent timeline's smoothChildTiming property is true, it will also adjust the timeline's startTime accordingly so that everything appears to play back smoothly (no jump/skip).

- Fixed issue that could cause an error in IE8 (and earlier) when clearProps was used to remove a transform-related property.

- Fixed issue that could (in rare situations) cause a 3D transform perspective to be negative

- If backgroundPosition is being tweened on an element that doesn't have a backgroundImage AND it is mixing % and px, it will skip interpolation to avoid a 404 error.

- Changed ScrollToPlugin's autoKill functionality so that now autoKill:false instructs the tween to force the scroll regardless of user interaction/circumvention. The default is autoKill:true.