docs: function showCapabilities( options, callback){
      options.url  = 'https://'+options.host+':'+options.port+SUPERVISOR_PATH_SHOW_CAPABILITY;
      options.ca = ssl_files.readCaChain(options.caFile);
      options.key = ssl_files.readFileContent(options.keyFile);
      options.cert = ssl_files.readFileContent(options.certFile);
  
      request(options, function (error, response, body) {
          if (!error && (response.statusCode = 200)) {
              var caps = (JSON.parse(body));
              callback(null, caps);
          }else{
              console.log(error);
              callback(new Error("Error connecting to the supervisor"), null);
          }
      });
  }