code: function session_or_abort(){
      return function(req,res,next){
          if(req.session !== undefined  && req.session.st){
              logger.debug('have session.  steady as she goes');
              // okay, pass control
              return next();
          }else{
              logger.debug('no session, switch to next route');
              return next('route');
          }
      }
  }
docs: session_or_abort
  
  if there is a session ticket from CAS in teh session, stored at
  session.st, then stay on this route.  If not, then abort and go to
  the next route, but calling next('route')
  
  This will only really work with express, as connect no longer has routing