Strip WP menu markup down to bare minimum

snippet.php

// Removes all CSS classes & ID's from menu items (only allows those listed)
add_filter('nav_menu_css_class', 'lit_strip_nav_menu');
add_filter('nav_menu_item_id', 'lit_strip_nav_menu');
function lit_strip_nav_menu($var) {
  return is_array($var) ? array_intersect($var, array(
		'current-menu-item',
		'menu-item',
	    	'menu-item-has-children',
	  	'sub-menu'
		)
	) : '';
}