Update commented out CDN asset host var usage.

Format has changed to be a complete url.
Use the hero image for the OpenGraph / Twitter images.
Logic to check for the hero image before trying to use it for Twitter / OG.
Don’t use CDN for carrierwave in development.
More explicitly check for the hero image.

@article.hero_image is present, even when no image.
Add some new fields to Content to contain the title and description meta tags.
Add meta title and description to article admin.
Update article display for desired title and description lookup logic.
Remove back end article title / description settings.
Populate author link on article page.
Add ability to manually assign the author for an article.
Revert "Add ability to manually assign the author for an article."

This reverts commit cc822342f0733a60a8f03ac6fec9cc69943adf4c.
Update compiled assets for changes in 0aec21.
Use bootstrap tabs to break up the article admin page.
Remove accidentally committed javascript.
Add related content to contents.
Add tab to the article admin to set related content.
Plumb related content into the article view.
Fix core content view logic - the fields might be blank but not nil.
Forgot to update compiled assets again.