Add another type of manual

This PR contains a number of changes necessary in order to allow us to view other Manuals, most notably:

* Adding a `ManualsPresenter` to allow us to tie information to the Manual rather than a Document/Section
* Frontend changes to remove hard coded information along with a bit of CSS refactoring
* A `ManualsRepository` to manage the fetching of the Manual and it's Sections
* Renaming the folder containing the placeholder HMRC content to it's full name so we can use the path to find it
* Implementing the design found on the [Trello ticket](https://trello.com/c/c6kTjaZ9/99-manuals-view-a-manual-5). Screenshot below: 

![screen shot 2014-05-29 at 16 22 48](https://cloud.githubusercontent.com/assets/449004/3119361/a05adc98-e745-11e3-94dc-0fc15fe4438c.png)