The JWR (JSON WebSocket Response) received from a Sails server.

@api public
@param  {Object}  responseCtx
=> :body
=> :statusCode
=> :headers

@constructor
function JWR(responseCtx) {
      this.body = responseCtx.body || {};
      this.headers = responseCtx.headers || {};
      this.statusCode = responseCtx.statusCode || 200;
      if (this.statusCode < 200 || this.statusCode >= 400) {
        this.error = this.body || this.statusCode;
      }
    }