fix for share image without host name
eliminate needless twitter card meta tags
Make code snippets less jarring to read
Merge branch 'master' of https://github.com/html5rocks/www.html5rocks.com
Fixes merge issues for #583
Kill background color for <code>
Merge branch 'master' of https://github.com/html5rocks/www.html5rocks.com
Merge branch 'master' of github.com:html5rocks/www.html5rocks.com into customelements-article
More editorial feedback from folks