FIXED slugfy and serialize methods from String module

- Slugfy was checking for the wrong variable (before removing the trailing slash)
- In modern browsers, objects carry the default parameter "classList". Now it is removed from the serialized string.

source/string/serialize.js

@@ -7,7 +7,9 @@ exports.serialize = function (obj) {
     var data = '';
 
     for (var key in obj) {
-        data += key + '=' + encodeURIComponent(obj[key]) + '&';
+        if (key !== 'classList') {
+            data += key + '=' + encodeURIComponent(obj[key]) + '&';
+        }
     }
 
     data = data.slice(0,-1);

source/string/slugfy.js

@@ -27,7 +27,7 @@ exports.slugfy = function (string) {
 
     // Remove trailing dash
 
-    if (root._.endsWith(string, '-')) {
+    if (root._.endsWith(slug, '-')) {
         slug = slug.slice(0, slug.length - 1);
     }