Created by: jonschlinkert
This pull request allows for different styling for active and hover states for navbar dropdown menu items.
Currently, when a navbar dropdown menu item is given an active state, the active dropdown item shares the same active styling as an active item on the navbar itself.
I separated the active and hover styles for dropdown menu items in dropdowns.less, to allow for different styling on each state.
Added right angle brackets to active nav items in navbar.less to provide the extra specificity required to allow active dropdown items to have different styling than active navbar items.
Added variable @dropdownLinkBackgroundActive to variables.less.
Updated example navbar in components.html to include a dropdown item with active state.