Put Animate script in Sttz.Tweener namespace since Unity 4+ supports MonoBehaviours outside the global namespace.
Fix Easing.ElasticOut mapping to InOut implementation.
Fix Elastic custom methods' arguments' default values not being set properly.
Fix errors on tween completion when tween was either not yet initialized or getting the start/end value throws an exception.
Fix easings going beyond 1 (e.g. Elastic) completing the tween early.
Add ToString method to Tween class.
Simpler creation of engine singleton.
Fix TweenGroup methods ignoring tweens that have been created in the current frame.
Bump to beta 2, add version constants to Animate class.