Rename EIM index

When using the index to construct a fake manual the title was incorrectly
being set as EIM Main Contents.
Adding placeholder JSON for EIM updates
Refactor Manual fetching to before_filter
Adding route and controller action for #updates
Rendering updates view

Adding a link to the updates from the header and an updates view. The
ChangeNotesPresenter takes the updates JSON and organises it by Year,
then by Day, then by Document.