Bug 1023663 - [User story] Calendar day view should start at 8 AM r=millermedeiros

Currently, the patch is for ui review. It is not ready for code review.
I would probably animate the `transform` since that should not affect the scroll and doesn't cause a new **paint** (which means it should be faster and use less cpu)..

```js
content.style.transform = 'translateY(' + scrollTo + 'px)';
```

I would also set the transition to only the `transform` property: `content.style.transition = 'transform ' + seconds + 's ease';` that should avoid problems in case we need to toggle other CSS properties.