Add breadcrumbs to documents/manuals/attachments
Merge pull request #136 from alphagov/add-breadcrumbs

Add breadcrumbs
Unify titles

- Index pages are now both "Your manuals" and "Your documents"
- Edit pages are "Edit X" where X is a manual, document, section or attachment
- New X is used for documents or manuals and Add X is used for sections or attachments
- Actual titles are used for show pages