Fix incorrect menu margins and size in WP 4.0-beta1. Apparently WordPress now supports thge ability to adding arbitrary CSS classes to submenu items, so the "menu-top" class that was previously harmlessly ignored now causes trouble with submenus.

git-svn-id: https://plugins.svn.wordpress.org/admin-menu-editor/trunk@949566 b8457f37-d9ea-0310-8a92-e5e31aec5664