<code> have overflow on x-axis on small resolution

Hi, I have PR for `<code>` wrap bug.
With small resolution I have overflow on x-axis (see screenshot or [check this page](http://theaqua.github.io/BrandButtons) (resize window, f.e.)) 

![Code wrap bug](https://f.cloud.github.com/assets/775692/2240554/66c4fe0a-9c9a-11e3-9eec-892c9bf28a9f.jpg)

I have 2 solutions:
* Add new class like `code.wrap` with `white-space: pre-wrap` (05e8abecc0d8979f8e79b231ad2274a15893d228)
* Or on small resolution made `white-space: pre-wrap` as default property (c3f76540b93d77c8e18a73d823d451611cc0ed99)