Add JSON documents

These are scraped files from the HMRC manual
Add govspeak gem

So we can covert markdown in JSON
Set up routes, read manual from /public/
Add in sections from JSON

- Make provisions for sections of sections
- Move bottom level list item to a partial
- Add helper for converting markdown to html
Add style for headers for colletions of subsections
Add width to hidden content

At some zoom levels the content was long enough to be visible so adding a width so it isn't
Fix id (was changed to underscores from hyphens)
Indentation fixes
Add <div class='govspeak'> wrap

Since all govspeak_to_html content will have a govspeak wrap, add this to the helper.
Merge pull request #11 from alphagov/add-real-data

Add real data scraped from a manual