Remove unused style guide partials.
Move style guide app to subfolder.
Using sinatra-export to create static version of site.
Remove procfile since no longer needed.
Change to relative links, since gh-pages can serve from subdirectory.
Remove unused helper methods.
Clean up gemfile and update gems.
Rename styleguide index.
Remove buildpacks and specific ruby version requirement.
Remove subheading on styleguide, clean up sidebar pattern a bit.
Merge pull request #304 from DoSomething/static-export

Static export
Release v4.0.4
Built assets for v4.0.4