choo should clear performance timers

right now we're relying on `choo-log` but actually `choo` should be responsible. If `choo-log` is not used the buffer can fill up which throws an error (after 200 or so events). Given it's an assignment it can easily be overwritten so making it part of `{ timings: true }` makes sense I think.

### code
```js
var hasPerformance = typeof window !== 'undefined' &&
window.performance &&
window.performance.onresroucetimingbufferfull
if (hasPerformance) {
window.performance.onresourcetimingbufferfull = function () {
window.performance.clearResourceTimings()
}
}
```