Minor: removed imgui demo window

src/App.cpp

@@ -215,7 +215,7 @@ void App::RenderUI(unsigned int FBOtexture)
 
     ImGui::NewFrame();
     ImGui::DockSpaceOverViewport();
-    ImGui::ShowDemoWindow();
+    //ImGui::ShowDemoWindow();
 
     {
         static int counter = 0;