isAuthenticated

Added a method on both the client-side and server-side that allows the
client to check in with ther server to see if it is still logged in. The
server provides a route at '/api/authenticated' that the client queries
and if the Authorization header comes back as a Bearer token, then
authentication continues, if it comes back as 'Revoked' then the UI
reflects that change.
Links to profile via logged-in state.
Profile + cosmetic changes

- Auth module now has separate methods for current user and greeting in
  order to split up messages in UI.
- User login now in navigation bar.
Reload page on login/logout

The page now reloads on user login and logout. This was done because the
page may look different to logged in user versus one that is logged out.