Add partial to display location (holdings) information on search results.

#### Note: This PR does not actually implement anything in the UI.  #291 will pull this (or part of this) partial into the results display in the accordion.

Partial can be rendered in a result by:

    <%= render partial: 'catalog/index_location', locals: { document: document } %>

Keeping #292 open until something is implemented in the UI.

### Single Item
---
![single-item](https://cloud.githubusercontent.com/assets/96776/3336562/fd23b1f8-f833-11e3-8508-df53c3849309.png)

### Multiple libraries
---
![multi-library](https://cloud.githubusercontent.com/assets/96776/3336563/fd256868-f833-11e3-94ae-2b6b4eda9b12.png)

### Multiple locations (and reserve)
---
![multi-location-and-reserve](https://cloud.githubusercontent.com/assets/96776/3336564/fd25ea18-f833-11e3-9a6b-5fd2708525f9.png)