Merge branch 'release/3.0.0'

Merge branch 'feature/remove-sample-files' into develop

Add layout examples to README

Add .md extension

Update README

Reduce config to bare minimum and remove sample content

Add layout to 404 page

Fix bug when site.twitter is null

Merge branch 'feature/documentation-and-demo' into develop

Update home splash page

Remove overlay header to simplify page

Fix typo in title

Make base_path available to all includes that need it

Disable breadcrumbs on paginated home pages

Fix broken breadcrumb links by including base_path helper

If page doesn't have a title fallback to site.title

Build home splash page

Adjust white-space around feature row items

Improve URL handling for internally and externally linked pages

Update about page