Added WAI-ARIA roles (document, navigation, main, note, contentinfo, search)

Navigation: main, top, breadcrumbs, footer

https://en.wikipedia.org/wiki/WAI-ARIA

http://www.w3.org/TR/wai-aria/roles
Merge pull request #86 from westurner/aria

Added WAI-ARIA roles (document, navigation, main, note, contentinfo, search)