Add visible and visible_set args, don't know where these had gone, I

Add visible and visible_set args, don't know where these had gone, I

2000-11-08  Havoc Pennington  <hp@pobox.com>

* gtk/gtktexttag.c (gtk_text_tag_class_init): Add visible and
visible_set args, don't know where these had gone, I thought they
used to be there

* gtk/testtext.c: Add a menu item to apply invisibility tag;
now we can test the feature and see that it's totally broken.