message: Better gateway error message for http.
diff: @@ -204,7 +204,7 @@ export namespace Gateway {
  if (connection.status === 200)
  resolve(JSON.parse(connection.responseText));
  else
  - reject(new IModelError(BentleyStatus.ERROR, `Server error: ${connection.status.toString()}`));
  + reject(new IModelError(BentleyStatus.ERROR, `Server error: ${connection.status} ${connection.responseText}`));
  });
  connection.addEventListener("error", () => reject(new IModelError(BentleyStatus.ERROR, "Connection error.")));
  