Add ability to edit forms and add new fields

This commit adds the ability to edit and modify existing forms.
On the technical side, it also adds a new reusable validation Facade which helps reduce duplicated code.

public/js/formbuilder.js

@@ -1,3 +1,4 @@
+// TODO: Add cleaner and less verbose solution found in formeditor.js
 $(document).ready(function() {
     $("#add").click(function() {
         var lastField = $("#buildyourform div:last");