get_sorted_time_zones()
Return the time zones sorted by some key. key must be a function that takes a TimeZoneInfo object and returns a value suitable for sorting on. The key defaults to the bias (descending), as is done in Windows (see https://web.archive.org/web/20130723075340/http://blogs.msdn.com/b/michkap/archive/2006/12/22/1350684.aspx)