UI Infrastructure: Animation API

[bryphe]

Implement #44

TODO:

• Consolidate math utilities into Revery.Core/Revery.Math
• Consolidate Time variant/type into the time in Revery.Core
• Clean up tests
• Create useAnimation hook, usage:

let v = useAnimation(Animated.floatValue(0.), { duration: Seconds(1.), easing: Animated.linear, delay: Seconds(0.), toValue: 1});

There's a couple of other hooks-based animation APIs I'd like to explore too:

• useSpring
• useTransition