Adds the `<Animated.Code>` component and a props type for a render or `exec` prop. Is it right that this should always return an `AnimatedNode<number>`?
Render prop or `exec` should be exclusive, based on how its implemented (`exec` takes precedence), but my TypeScript experience is too limited to figure that out.
Trying to use reanimated with typescript results in bunch of `Namespace 'Animated' has no exported member 'EasingFunction'` errors because `Animated.EasingFunction` is not being exported.
