Tabzilla conflict with collection view & footer margin tweak.

The z-index patch resolves the issue, but certainly isn't ideal. Might be worth exploring options where the collection sidebar is no longer `position: fixed` as it is a bit awkward.

![screen shot 2013-07-18 at 9 35 53 pm](https://f.cloud.github.com/assets/747641/823981/cae62582-f02c-11e2-9289-f883a492f29f.png)