Bugfixes, dialog improvements

* It is now possible to pass an element as the dialog message to have it inserted as the body.

dom.js

@@ -56,6 +56,8 @@ class DomHelper {
      * @returns 
      */
     append(tag, children) {
+        // Handle null, to make it easy to skip items with conditionals
+        if (children === null) return;
         //console.debug(`append: ${tag.nodeName}`, children);
         if (typeof children == 'object' && children instanceof Element) {
             //console.debug(`-> appended element`);