Bikeshed the design of the bar graphs

I know this is a pretty bikeshedesque pull request, so no hard feelings if you don't merge it.

This makes a couple changes to the styling of the bar graphs.

First, the percents are moved inside the bars and the colors inverted. When there is no space for them inside the bars, they are appended as they previously were.

Second, the bars are expanded so that the available width is filled with the longest task, rather than the widths being a percentage of total time.

# Before

![Before](http://i.imgur.com/57MjfV8.png)

# After

![After](http://i.imgur.com/e7F6YHL.png)

Either way, grunt-time is super helpful, thanks for all your work.