Fixed Firefox autoHeight issue in tabbed interface SCSS.
Merge pull request #2503 from pjackson28/v3.0

Lightbox: Improved handling of WAI-ARIA for image and documents
Removed the branch option for the working example checkout
Reworked Firefox autoHeight fix and added comment for context.
Merge pull request #2486 from EricDunsworth/v3.0-tabs-ff-auto-height

Tabbed interface: Fixed Firefox autoHeight issue in SCSS.
Fixed scrolling of archived content.