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.
every time you see an if/else make sure it's really needed.. if/else makes code way harder to understand and it is usually where bugs hides.. this is simpler/cleaner:

```js
return Math.min(scrollTop, maxScrollTop);
```