Update highlightjs to 8.3.0.
Update normalize-css to 3.0.2.
Update foundation to 5.4.7.
Check-in Gemfile.lock.
Use https for link to demo site.
Fix link to humans.txt.
Use https in _config.yml.
Ruby to 2.1.4 in .travis.yml.
Add caching for Travis; exclude vendor.
Merge remote-tracking branch 'upstream/master' into project-site

Conflicts:
	README.md
	_assets/stylesheets/_settings.sass
	_config.yml