Bit more cleanup

scripts/Singleton/UI.gd

@@ -0,0 +1,25 @@
+class_name UISystem extends Control
+
+enum Layer {
+	Game,
+	VN,
+	Test,
+	Debug
+}
+
+func addSubscene(subscene:Control, layer:Layer) -> void:
+	subscene.originalParent.remove_child.call_deferred(subscene)
+
+	match layer:
+		Layer.Game:
+			$LayerGame.add_child.call_deferred(subscene)
+		Layer.Debug:
+			$LayerDebug.add_child.call_deferred(subscene)
+		Layer.VN:
+			$LayerVN.add_child.call_deferred(subscene)
+		_:
+			push_error("Invalid layer: " + str(layer))
+			return
+
+func removeSubscene(subscene:Control) -> void:
+	subscene.get_parent().remove_child(subscene)