created a bug for it: https://bugzilla.mozilla.org/show_bug.cgi?id=996841 - but I'm unsure if I should do it before this patch or not.. (updating dependencies is a PITA)...

I'm considering the option to push it like:

```js
function waitForElement(el){
  client.helper.waitForElement(el, { timeout: 3000 });
}
```

it will be ignored for now but in the near future we will implement the improvement... that way I can merge both patches today and worry about the marionette-helper only next week.