Returns HTML for a menu link and submenu.
$variables: An associative array containing:
function theme_menu_link(array $variables) {
$element = $variables['element'];
$sub_menu = '';
if ($element['#below']) {
$sub_menu = drupal_render($element['#below']);
}
$output = l($element['#title'], $element['#href'], $element['#localized_options']);
return '<li' . drupal_attributes($element['#attributes']) . '>' . $output . $sub_menu . "</li>\n";
}