Ensure manifest is cached between calls.
Prevent automatic registration running multiple times

Fix up automatic registration details.
Respect documentation base href for link to home.
If a folder has no children, default to menu

This happens in the event of the documentation home page.
Correct title generation for index files in entity root

Previously would output the language code as the title 'En'. This double checks whether the file is at the root of the entity and if so, it'll use the entity name.