Flip the year/month separators

add_filter('tribe_events_list_the_date_headers', 'flip_tribe_year_month_separators');

function flip_tribe_year_month_separators($html) {
    $year = strpos($html, "<span class='tribe-events-list-separator-year'>");
    if (false === $year || 0 === $year) return $html;
    else return substr($html, $year) . substr($html, 0, $year);
}