Timeline segments should expand or show tooltips on mouseover

[glacials]

Some splits are so small relative to the run that the width allocated to them in the timeline chart is not nearly enough to display the split title or duration.

Example: http://splits.io/YtJF

Simple solution

Add a mouseover tooltip to each split, and display that split's title and duration in the tooltip.

Pretty solution

Make splits smoothly expand their width on mouseover to be wide enough to display their information. The widths of all other splits would need to temporarily shrink to compensate, which in itself could be a cool animation.

Alternative pretty solution

The split could expand on top of the other splits and gain a box-shadow to make it look as if it is above the others. An animated box-shadow that increases from 0 over a second or so could make it look like the split is being raised out of the timeline bar. This solution would be pretty, but might be too flashy for something as simple as a mouseover.