Add exception include

Contains the HTML for the popup and makes it easy to use
Add rendering of exception include + CSS
No longer called international.html
Add international.html as @lpn25 mentions in #241
Add Twitter exceptions, currently a placeholder
Add link for Twitter, add PayPal exception
Added the domain registrar Badger.com
Merge pull request #520 from mcdanielisaac/master

Added the domain registrar Badger.com
Update CONTRIB.md for exceptions/restrictions section
Add exception template, add none placeholder
Update data to new format, update restrictons.html
Add updated exceptions/restrictions as per #241
Merge branch 'master' into gh-pages
Merge branch 'gh-pages' of github.com:jdavis/twofactorauth into gh-pages