Add links to the top of the example page to the source scss

![screen shot 2014-03-28 at 1 44 55 pm](https://cloud.githubusercontent.com/assets/223180/2553042/c5e1783a-b6a0-11e3-9029-4671129b35bc.png)
![screen shot 2014-03-28 at 1 45 06 pm](https://cloud.githubusercontent.com/assets/223180/2553043/c5e6ad1e-b6a0-11e3-9c00-42cac3299a3b.png)

From https://github.com/thoughtbot/neat/issues/158