Update cheapseats

We would like to use the version that lets you test a single dashboard, 
since that’s quicker than waiting for them all to run when you’re
trying to diagnose an issue.
Merge pull request #869 from alphagov/bump-cheapseats

Update cheapseats
Add schema.org microdata

Based off a conversation with @psd, wanted to add a little extra to our
output.

Longer term, this should be moved into the data model and reflected in
the API as well as markup.

Placeholder for a future conversation.
Merge pull request #870 from alphagov/feature/schema.org-annotations

Add schema.org microdata
Add big screen link to overview and detailed dashboards only
Merge pull request #871 from alphagov/big-screen-link

Add big screen link to overview and detailed dashboards only
Make big screen link absolute

Big screen is hosted on a different domain, so a relative link
returns a 404.
Merge pull request #872 from alphagov/big-screen-absolute-link

Make big screen link absolute
Introduce the section module type server-side
Introduce the section module type client-side
Increase specificity of styles
Style section heading
Suppress linkable heading tag for sections
Remove unnecessary code
Stub out Stagecraft for a sectioned dashboard