docs: handle error

Author: joscha

README.md

@@ -24,7 +24,7 @@ crawler.addRunner('a11y-dev-tools', new A11yDeveloperToolsRunner());
 crawler.crawl()
     .then((data) => {
         console.log(JSON.stringify(data.results, true, 2));
-    });
+    }, (err) => console.error(err));
 ```
 
 This project is in no way affiliated with Google, Inc.

examples/tonic.js

@@ -1,11 +1,13 @@
-/* eslint-disable no-console */
+'use strict';
+
 const CrawlKit = require('crawlkit');
 const A11yDeveloperToolsRunner = require('crawlkit-runner-accessibility-developer-tools');
 
 const crawler = new CrawlKit('http://www.google.com');
 crawler.addRunner('a11y-dev-tools', new A11yDeveloperToolsRunner());
 
+/* eslint-disable no-console */
 crawler.crawl()
     .then((data) => {
         console.log(JSON.stringify(data.results, true, 2));
-    });
+    }, (err) => console.error(err));