Keep template source nicely formatted
Unify header partials and include in layout
Stop wrapping multiple articles with <section> when list posts
Keep post excerpts short
Move pagination control into layout

Also replace `pageUrl` with `page_url`
Include Prism to syntax highlight code samples
Use Prism's Okaidia theme
Remove theme name from credits
Include integration hooks for Twitter

See https://dev.twitter.com/docs/cards
Include integration hooks for Open Graph

See http://ogp.me/