Revert "vendor compiled assets"

This reverts commit d271af153adefb134ecfed032e1897d1994314bc.
Added rails_12factor gem to fix Heroku asset precompile. [by @masondesu]
Fixed issue with asset pipeline fingerprinting not happening on an image in JST. [by @masondesu]
Use image_url helper in chosen.css.scss [by @masondesu]
Added asset path helpers for symbolset [by @masondesu]