Made list item highlighting more like 1.4

Before:

![screen shot 2014-05-28 at 16 34 25](https://cloud.githubusercontent.com/assets/1578238/3110639/9ca1040e-e6a7-11e3-8591-a94609cbc242.png)

After:

![screen shot 2014-05-28 at 16 40 38](https://cloud.githubusercontent.com/assets/1578238/3110705/68a9d7f6-e6a8-11e3-9079-4d866cab1860.png)

I'm not entirely sure this is better. Just an option for the design team to discuss. For reference, here's what 1.4 looks like:

![screen shot 2014-05-28 at 16 37 33](https://cloud.githubusercontent.com/assets/1578238/3110669/ec50fde2-e6a7-11e3-9e41-e0d88b2552b8.png)