Clean project structure.

src/ui/ui_controls/StackWidget.cpp

@@ -0,0 +1,28 @@
+#include "StackWidget.h"
+
+#include <iostream>
+
+StackWidget::StackWidget()
+{
+
+}
+
+std::unique_ptr<StackWidget> StackWidget::Create()
+{
+    return std::make_unique<StackWidget>();
+}
+
+void StackWidget::showChild(Widget* target)
+{
+    for(auto& child : mChildren)
+    {
+        if(child.get() == target)
+        {
+            child->setVisible(true);
+        }
+        else
+        {
+            child->setVisible(false);
+        }
+    }
+}