title: php array unique on two arrays
body: <p>Two PHP arrays:</p>
  
  <pre><code>$array1 = array(1,2,3,4,5);
  $array2 = array(1,2,3,4,5,6,7,8,9,10);
  </code></pre>
  
  <p>Now how can I end up with an array like this:</p>
  
  <pre><code>$array3 = array(6,7,8,9,10);
  </code></pre>