onRest seems to cause React-Motion to ignore rerenders

This `onRest` callback doesn't work:

``` js
@autobind
handleRest() {
this.setState(getNextTransitionState);
}
```

However, this one works as expected:

``` js
@autobind
handleRest() {
window.setTimeout(() => {
this.setState(getNextTransitionState);
}, 0);
}
```