Initial layouts for metadata panels and sections in record view

Closes #11 

* Added basic framework for record view sections (Browse nearby, metadata panels and sections)
* On smaller screens, the panels and sections are stacked as one column

When we have logic for rendering the panels and sections, we need to add tests to the layout elements. 

Screenshots with dummy panels and sections data - 

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![searchworks-issue11-1](https://cloud.githubusercontent.com/assets/302258/2924954/18f862c0-d741-11e3-8faf-155b84862ce5.png)
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![searchworks-issue11-2](https://cloud.githubusercontent.com/assets/302258/2924973/91337b26-d741-11e3-8516-29401ce2db05.png)