title: Convert unix timestamp to human readable date
body: <p>Is there a contemporary way to convert unix timestamps to a human readable date?
  Since I want to circumnavigate the year 2038 problem, I want to use int64s.
  I target to convert e. g. 1205812558 to </p>
  
  <p>year = 2008, month = 3, day = 18, 
  hour = 17, minute = 18, second = 36</p>
  
  <p>All I have is now</p>
  
  <pre><code>auto year = totalSeconds / secondsPerYear + 1970;
  // month and day missing
  auto hours = totalSeconds / 3600 % 24;
  auto minutes = totalSeconds / 60 % 60;
  auto seconds = totalSeconds % 60; 
  </code></pre>