Merge branch 'release/3.3.5'

Add `en` default text to `site.locale` strings
- Close #407

Merge branch 'release/3.0.0'

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

Make base_path available to all includes that need it

Only show post pagination if there are previous or next posts

Improve pagination styling

Style tweaks to pagination, right sidebar, and background color

Add post pagination to sidebar and make minor styling alterations