Layers Breadcrumb: fix extra space in small screens

Before:
![screen shot 2014-10-17 at 10 47 06](https://cloud.githubusercontent.com/assets/1152640/4676383/43b07ce2-55da-11e4-8cf3-ad6c4cf1123d.png)

After
![screen shot 2014-10-17 at 10 47 22](https://cloud.githubusercontent.com/assets/1152640/4676382/43aa71e4-55da-11e4-9ab3-bac389ebe17d.png)

Hmm... I'm apprehensive about needing to do this. What's causing the extra space? Is it because of the ad? What happens if there's no ad for example?