Fixed demos
Fixed how demos where referencing o-hierarchical-nav and made header not init o-hierarchical-navs when they have previously been initialized, normally by the o.DOMContentLoaded event being dispatched. Also removed demo_common.scss, not needed
Merge branch 'doc-fixes' into demo-fixes
Fixed merge conflicts
Merge pull request #73 from Financial-Times/demo-fixes

Fixed o-hiearchical-nav integration and other demo fixes