public FontTweener(EasingAlgorithm easing) : base(easing) { }
public Tweener(EasingAlgorithm easing) { this.Easing = easing; }
public ColorTweener(EasingAlgorithm easing) : base(easing) { }
public NumericTweener(EasingAlgorithm easing) : base(easing) { }