Merge pull request #2281 from learningequality/release-0.12.0

Release 0.12.3
metadata for 0.12.3
Merge branch 'release-0.12.0'
Merge pull request #2308 from learningequality/release-0.12.0

Release 0.12.5
Merge pull request #2351 from learningequality/release-0.12.0

Release 0.12.6
Hook global alerts into bootstrap 3
Fix JS alerts; Signup works.
Sticky footer and elements moved to partials
finished bugs in nav bar with merge changes
fixed a few more bugs in manage nav bar and some of issues that dylan raised
stops the teacher navigation from showing up on landing page
Merge branch 'navigation-changes' of github.com:jtamiace/ka-lite into develop-polishing
Merge pull request #13 from jtamiace/navigation-changes

Navigation changes
Merge branch 'develop-polishing' of github.com:dylanjbarth/ka-lite into develop-polishing
Fix up zone management page.
Make question marks mobile friendly
changes to update videos and language pages. more bootstrap
Merge branch 'navigation-changes' into develop-polishing
Add `hacks_for_phantomjs()` method.
Merge pull request #2373 from mrpau/hotfix/add_phantomjs_hacks

Add `hacks_for_phantomjs()` method for `release-0.12.0` branch.