Connect add and remove buttons

src/Tools/tim_tool/ui/app-window.slint

@@ -4,6 +4,11 @@ import { MainTab }   from "./tab/main-tab.slint";
 import { TabWidget } from "std-widgets.slint";
 
 export component MainWindow inherits Window {
+    in-out property main_tab_vram_file_list <=> tab.vram_files;
+
+    callback main_tab_add_file_clicked    <=> tab.add_file_clicked;
+    callback main_tab_remove_file_clicked <=> tab.remove_file_clicked;
+
     title: "TIM Tool 0.1.0";
     width:  tab_widget.width;
     height: tab_widget.height;