added role of navigation to every div with navbar class and a callout explaining the function in the 'basic navbar' section
added navigation role to a few missed navbars
Add role="navigation" to bootstrap documentation navbar
Add role="main" to documentation content
Merge branch 'navbar_navigation_role' of github.com:dobtco/bootstrap-accessible into navbar_navigation_role
added missing role
Add additional roles and move "main" roles into the proper places (hopefully)
Merge branch 'navbar_navigation_role' of https://github.com/dobtco/bootstrap-accessible into navbar_navigation_role
Merge pull request #11 from dobtco/navbar_navigation_role

Adds navigation roles to examples, and WAI ARIA Landmark roles to documentation template.