fileItem.js: Create menus lazily
Now menus don't get created until they're needed.
And since menus often won't be needed at all, this conveniently works around apparent leaks in gnome-shell PopupMenu (#104 (closed)).
Now menus don't get created until they're needed.
And since menus often won't be needed at all, this conveniently works around apparent leaks in gnome-shell PopupMenu (#104 (closed)).