title: Get a gregorian date from Hijri date strings
body: <p>I would like to get a gregorian date from the Hijri date indexs. </p>
  
  <p>e.g</p>
  
  <pre><code>getDate(1436, "SHawwal", 18)
  </code></pre>
  
  <p>This should return </p>
  
  <pre><code>3rd August 2015
  </code></pre>
  
  <p>How could I do the conversion ? </p>