Xiao Tan

fix: endless concat

2

This pr fix #620

tweening to arrays of values has bug

2

`_valuesEnd[property]`'s length will grow endless, because it's a reference to `this.valuesEnd` https://github.com/tweenjs/tween.js/blob/8db070d25a82c19772352bbcbc33a326e6882b4e/src/Tween.ts#L138-L150 checking this demo, just click the start button twice or more: https://jsbin.com/hulidowipa/edit?html,js,output