Refactor content-store test fixture data.

Use json files instead of methods with hardcoded hashes
Disable formatted routes.

This app doesn't have any support for alternative formats.
Support contact pages at new URL.

Contact pages are going to be served from
/government/organisations/<org_slug>/contact/<contact_slug> instead of
the original url of /contact/<org_slug>/<contact_slug>.  This change
makes this app support both schemes.  The old one will be removed once
everything has switched over.
Remove trivial page_class helper.

It wasn't really adding anything other than an additional level of
indirection.
Update breadcrumbs to link to correct index path
Merge pull request #7 from alphagov/url_changes

Support contact pages at new URL