Fix Error when onEnd calls parent and removes component
Fix Error when onEnd calls parent and removes component

Fixes #24
Also require the now pulled out tween-functions library

GuoYongfeng/react-tween-state,chenglou/react-tween-state,cyhunter/react-tween-state,cyhunter/react-tween-state,GuoYongfeng/react-tween-state,mcanthony/react-tween-state,swhite24/react-tween-state