code: def GET_namespace_info( self, path_info, namespace_id ):
          
          if not check_namespace(namespace_id):
              return self._reply_json({'error': 'Invalid namespace'}, status_code=400)
  
          blockstackd_url = get_blockstackd_url()
          namespace_rec = blockstackd_client.get_namespace_record(namespace_id, hostport=blockstackd_url)
          if json_is_error(namespace_rec):
              # error
              status_code = namespace_rec.get('http_status', 502)
              return self._reply_json({'error': namespace_rec['error']}, status_code=status_code)
  
          self._reply_json(namespace_rec)
          return
docs: Look up a namespace's info
          Reply information about a namespace
          Reply 404 if the namespace doesn't exist
          Reply 502 for any error in talking to the blocksatck server