Rework Project Ultra

- Added container
- Made container the base of Layout
- Set Containers theirself as pParent for Elements on Push

source/ultra/layout.cpp

@@ -2,14 +2,11 @@
 
 namespace PD {
 namespace Ultra {
-PD_API void Layout::Add(ElementBase& elem) { *pElements.Allocate() = &elem; }
-
 PD_API void Layout::SetFont(PD::Li::Font& font) { pList.SetFont(&font); }
 
 PD_API void Layout::Render() {
   pList.Clear();
-  for (auto& it : pElements) {
-    it->Update(pCanvas);
+  for (auto& it : GetElements()) {
     it->Draw(pList);
   }
 }