Animation player for ui

● public static void PlayAutoAnim (GameObject obj, AnimationClip animClip) 
● public static void Play (GameObject obj, AnimationClip animClip) 
● public static void Play (GameObject obj, string animStateName) 
● public static void Stop(GameObject obj, AnimationClip animClip) 
● public static void StopAtFirstFrame (GameObject obj, AnimationClip animClip) 
● public static void RevertPlayAnim (GameObject go, AnimationClip animClip) 

● PS: UIAnimLegacyForUGUI，[Hack]矫正修改对象alpha值无效的处理