title: Merge 3 flat, indexed arrays into one flat, indexed array
body: <p>I'd like to merge three arrays like this:</p>
  <pre><code>$a = array(1,2,3,4);
  $b = array(5,6,7,8);
  $c = array(1,2,3,4);
  </code></pre>
  <p>into one big array so that the output would be:</p>
  <pre><code>$result = array(1,2,3,4,5,6,7,8,1,2,3,4);
  </code></pre>