Add target="_blank" and rel="nofollow" to all formatted links

closes #247

src/Core/Formatter/Formatter.php

@@ -42,6 +42,15 @@ class Formatter
 
         event(new FormatterConfigurator($configurator));
 
+        $dom = $configurator->tags['URL']->template->asDOM();
+
+        foreach ($dom->getElementsByTagName('a') as $a) {
+            $a->setAttribute('target', '_blank');
+            $a->setAttribute('rel', 'nofollow');
+        }
+
+        $dom->saveChanges();
+
         return $configurator;
     }