Refactor user service.

This hopefully makes it safer if globals aren't available.
Fix relative links in article body
Fix both image and link refs
Add 'Feeds' link to header.
Merge branch 'master' into front-end
Rake task to re-validate articles
Update rake
Add alias names for article url and body
Add more validation functionality to article scrubber
Merge remote-tracking branch 'origin/master' into front-end
Add 'Feeds' route, view and controller.