title: Round negative integer quotient towards negative infinity
body: <p>It appears that integer divisions in Swift round towards zero rather than towards the lower number. This means, for instance, that <code>-1 / 2</code> will be 0 instead of -1.</p>
  
  <p>Is there a way to tell Swift to round towards the lower number? I know how I can "simulate" it, but if there's a native solution, I'd rather use it.</p>