Popular-in-tag related content on advertisement features

Also style the related containers á la other ad feature containers

And remove unneeded containers from ad feature articles' footer

### Before

![screen shot 2014-10-16 at 16 07 12](https://cloud.githubusercontent.com/assets/74132/4664828/77eaba7a-5546-11e4-981f-7e50a68b8532.png)

### After

![screen shot 2014-10-16 at 16 07 15](https://cloud.githubusercontent.com/assets/74132/4664833/7d04ee9a-5546-11e4-871e-986d70c88a78.png)

Could this `Option` be a `Seq`?