Added wcf certificate authentication

Everyone is identified using certificates. httpBindings use message certificate authentication while the Dataservices being a webBinding support only https channel and client certificate authentication. To do that in IIS you can either IIS Client Certificate Mapping Authentication or if you have a AD the client certficate mapping.
To configure that, http://www.iis.net/configreference/system.webserver/security/authentication/iisclientcertificatemappingauthentication.