Updated to reference root namespace \Exception

If you ever got a curl error you would actually end up with an exception from trying to throw the exception:

`Class 'overint\Exception' not found`

Author: aknosis

src/MailgunValidator.php

@@ -43,7 +43,7 @@ private function queryMailgun($email)
         curl_close($curl);
 
         if ($err) {
-            throw new Exception('Curl Error: ' . $err);
+            throw new \Exception('Curl Error: ' . $err);
         } else {
             return json_decode($response);
         }