Feature #985 Managing Facebook Connections

I've renamed the OpenID view in the user settings/Login to Single Sign On.
The connected OpenIDs are still listed there.
Now if the user is connected to Facebook, the user will see Facebook in the list of Single Sign Ons.
The connection to Facebook can be removed, just like OpenID connections.
A new connection to Facebook can be established with a click on a link, just like with OpenID.