Bug 799273 - [ro] Get Involved page, fix responsive design all locales

* Add email address
* Add 'ro' to LOCALES_WITH_MOZ15
* Add localized banner + css rule
* Fix CSS for slides 2 and 6
* Fix all localized rules (added .on class to be active only on the slideshow)
Merge pull request #1112 from flodolo/bug799273_ro

Bug 799273 - Get Involved [ro], fix responsive design