Snapshot Freeze Time: add Langolier tag for new (invisible) avatars.

If an avatar TP's in while you are in Freeze Time mode, they now have a
visible tag with the tag 'Langolier' in it. After exiting Freeze Time
mode they become visible. Before they would stay invisible.

indra/newview/llfloatersnapshot.cpp

@@ -2977,6 +2977,8 @@ void LLFloaterSnapshot::onClose(bool app_quitting)
 	// Set invisible so it doesn't eat tooltips. JC
 	gSnapshotFloaterView->setVisible(FALSE);
 	gSavedSettings.setBOOL("SnapshotBtnState", FALSE);
+	gSavedSettings.setBOOL("UseFreezeTime", FALSE);
+	impl.updateLayout(this);
 	destroy();
 }