title: How to sort an array of strings representing month and year?
body: <p>I have an array of strings in my code which represents a series of months in years. Something like this:</p>
  
  <pre><code>let arrayOfMonths = ["May 2017", "January 2018", "August 2016", "January 2015", "June 2017"]
  </code></pre>
  
  <p>I'd like to <strong>sort</strong> it, by following the classic succession of months and years, so I'd like an output like this:</p>
  
  <pre><code>let sortedArrayOfMonths = ["January 2015", "August 2016", "May 2017", "June 2017", "January 2018"]
  </code></pre>
  
  <p>How can I do it in Swift 3? Thanks.</p>