Merge pull request #127 from tobyk100/master

Add viewport for mobile tweaking.
Merge pull request #128 from tobyk100/master

Made videos fit better on mobile.
Fix localization mix up
links and spacing tweaks
Update translation volunteer links
Translations
I18n.with_locale
Add message with links to show users that have finished all levels
Fix bad possessive
Sanitize footer strings
Translations
Add indexes to foreign keys
Merge pull request #129 from brandonbloom/fk-indexes

Add indexes to foreign keys
fix horizontal scrolling on 900 pixel wide devices
Fix migration
Merge pull request #130 from code-dot-org/fixhorizontalscrolling

fix horizontal scrolling on 900 pixel wide devices
Add back doctype.
Update schema.