Instances of `SPTScrollViewScrubberController` control a scrubber view to quickly scroll through an `UIScrollView` or any of its subclasses like `UITableView` or `UICollectionView`.
 
 It was inspired by [NSScreencast episode 97: Scrolling Nub (11/28/2013)][1].

[1]: http://nsscreencast.com/episodes/97-scrolling-nub