Fix bug about "module is not defined"
Fix bug about "module is not defined"

In some environments , there may be a global object named exports. 
for example, some code maybe do this :
```
var exports = exports || window;
```

So ,  I think check module & exports both is a better way.
CasualBot/tween.js,CasualBot/tween.js,CasualBot/tween.js