title: Sorting elements based on condition
body: <p>HTML:</p>
  
  <pre><code>&lt;div class="album"&gt;
      &lt;div class="listing"&gt;
          &lt;a href="#" class="btn hidden"&gt;Button&lt;/a&gt;
      &lt;/div&gt;
      &lt;div class="listing"&gt;
          &lt;a href="#" class="btn"&gt;Button&lt;/a&gt;
      &lt;/div&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>Pseudo Code:</p>
  
  <pre><code>in each album
      each listing 
          hidden = find ('.btn.hidden')
      remove and append (move) all hidden to the bottom
  </code></pre>
  
  <p>I'm not sure how to remove elements and then append?</p>