Fix Bug 1087020: Demo deatil page mobile view

Added clearfix() to mobile column declaration, this could break stuff.
BUG 1084110: Upgrade Stylus & Clean CSS

All ways good to have most recent versions of things both updates inclue bug fixes and the Clean CSS one saves us yet more white space.

Small change to the font-awesome.styl file to remove an unnecissary call that was throwing new Stylus into an infinate loop.
Bug 1083889: Manually activate Optimizely test
Merge pull request #2851 from openjck/1083889-manually-trigger-sticky-button-test

Bug 1083889: Manually activate Optimizely test
Merge pull request #2849 from stephaniehobson/BUG-1084110-upgrade-stylus

FIX BUG 1084110: Upgrade Stylus & Clean CSS
Merge pull request #2848 from stephaniehobson/BUG-1087020-demo-detail-page

Fix Bug 1087020: Demo detail page mobile view
bug 1084110 - Update paths to stylus and cleancss
Merge pull request #2854 from darkwing/update-stylus-location

bug 1084110 - Update paths to stylus and cleancss
BUG 1087015: Demos - menu

Fix "browse by technology" menu being open by default.
Bug 1087015: Demo Stuido - gallery page

- Gallery page now stacks
- Replaced JS that created "card" effect on hover with pure CSS
- Revived background image on not-the-landing-page
- Restricted button styles to act within main content
- Added clearing to all columns when they collapse.
Merge pull request #2853 from stephaniehobson/BUG-1087015-demos-gallery

Bug 1087015: Demo Stuido - gallery page
Merge pull request #2855 from stephaniehobson/BUG-1087015-demo-menu

BUG 1087015: Demos - menu