Fix form submission (#129)

* Fix check for radio and checkbox inputs

* Fix GET form submission

* Add example forms for testing

* Refactor query string building

example/example.js

@@ -20,7 +20,8 @@ document.addEventListener("pjax:success", function() {
 document.addEventListener("DOMContentLoaded", function() {
   var pjax = new Pjax({
     elements: [".js-Pjax"],
-    selectors: [".body"]
+    selectors: [".body", "title"],
+    cacheBust: true,
     // currentUrlFullReload: true,
   })
   console.log("Pjax initialized.", pjax)