Allow dialogues to be hidden or shown

To do this, MENU and SUBMENU are split into two types (at last), and
a Widget type is introduced. This should allow lots of code to be
removed at some point.

cmd/loader/main.go

@@ -157,24 +157,24 @@ func loadMenus() {
 
 	for _, menu := range menus {
 		fmt.Printf("    * `%s`: objects=%v fonts=%v\n", menu.Name, menu.ObjectFiles, menu.FontNames)
-		for _, record := range menu.Records {
-			displayRecord(record, 2)
+
+		for _, group := range menu.Groups {
+			// TODO: display group
+			for _, record := range group.Records {
+				displayRecord(record, 2)
+			}
 		}
 	}
 }
 
 func displayRecord(record *menus.Record, depth int) {
-	content := fmt.Sprintf("id=%v type=%v sprite=%v", record.Id, record.Type, record.SpriteId)
+	content := fmt.Sprintf("id=%v type=%v sprite=%v", record.ID, record.Type, record.SpriteId)
 
 	if !record.Active {
 		content = "(" + content + ")"
 	}
 
 	fmt.Printf("%s* %s\n", strings.Repeat("    ", depth), content)
-
-	for _, child := range record.Children {
-		displayRecord(child, depth+1)
-	}
 }
 
 func loadFonts() {