Set application max width

:fork_and_knife: On large displays Supermarket is really really stretched out this adds a max width to much of the application so things look a bit more sane on large displays.

![screen shot 2014-06-18 at 4 01 09 pm](https://cloud.githubusercontent.com/assets/316507/3319778/cd40a52e-f723-11e3-8724-c979ac19a24a.png)
![screen shot 2014-06-18 at 4 01 17 pm](https://cloud.githubusercontent.com/assets/316507/3319780/cec888f8-f723-11e3-8ff0-9625aa0ae04d.png)
![screen shot 2014-06-18 at 4 01 48 pm](https://cloud.githubusercontent.com/assets/316507/3319783/d12364ce-f723-11e3-878c-1d3449bbf638.png)
![screen shot 2014-06-18 at 4 02 16 pm](https://cloud.githubusercontent.com/assets/316507/3319787/d2c6c1e0-f723-11e3-94f8-57edcd2207a0.png)

Ah yes, `.cookbook_columns` should be a `<ul>`. I'll resolve this shortly.