Change More hiding/showing to CSS class from explicit block/none.

When theme wants to use something else than display: block; the old
method did not work.

themes/original/css/theme_right.css.php

@@ -667,6 +667,10 @@ ul#topmenu ul a {
 
 ul#topmenu .submenu {
     position:           relative;
+    display: none;
+}
+ul#topmenu .shown {
+    display: block;
 }
 
 ul#topmenu ul {