A sticky navigation

Intro
This is a proposal to add some persistence to part or all of the top right navigation which carries: Username, talk, watchlist etc

Why

 * Notifications are being carried in the top right navigation and soon enough other critical 'Keep top of mind' things related to flow and watchlist might be indicated there also.
 * Because the top right menu is small and impersistent, talk and other things in the current version of echo lose persistence which is necessary as you vertically scroll on the page.