title: Get list of languages in Qt5
body: <p>I want to get the list of ISO 639 languages, from <code>QLocale</code>.  I can use this code to get all combinations of language/country.</p>
  
  <pre><code>QList&lt;QLocale&gt; allLocales = QLocale::matchingLocales(
          QLocale::AnyLanguage,
          QLocale::AnyScript,
          QLocale::AnyCountry);
  </code></pre>
  
  <p>This is exactly what I need. I assume I can filter out the list manually, but does a better alternative exist?</p>