Add Mozilla Persona Omniauth Gem and initializer
Add (ui-only) Persona button to login modal
Add basic Persona functionality

1. No session integration yet, so automatic login/logout events are suppressed.

2. Popup blockers must be disabled: submits form to target="_blank"
Use AJAX for submitting Persona credentials.

Fixes issue with needing to unblock popups.
Make Persona configurable
add basic coding style guidelines to CONTRIBUTING.md
Add specs for Enum class
Update SiteSettingExtension to use new Enum class
Removed unused `type` parameter in site settings. Remove hardcoded date reference in en.yml
Missed reference to `type`
Get secret_token from ENV['SECRET_TOKEN'] (e.g. for Heroku)
Fix display host for onebox
Fix weirdly indented code
trying to get jshint to work on travis
bumped rb-inotify gem version

as per the recommendations given by guard
Change the name displayed in the header on profile update
Removing unnecessary Rails.env check
make Enum#valid? specs test the right thing
move IncomingLink callbacks into their own methods
minox TOS HTML fixes