title: bootstrap thumbnails second row not sitting correctly
body: <p>I seem to run into this problem all the time and I'd love some advice from a bootstrap guru.</p>
  
  <p>the following <a href="http://jsfiddle.net/rcfearn/WgU9b/5/" rel="nofollow">jsfiddle</a> demonstrates the problem, because there's a row-fluid on the parent container only the first row of the thumbnails sits correctly the rest are inset (i.e. the third thumbnail does not sit directly below the first thumbnail).</p>
  
  <p>the code is as follows:</p>
  
  <pre><code>&lt;div class="container row-fluid"&gt;
      &lt;div class="span6"&gt;
          &lt;p&gt;som content here&lt;/p&gt;
      &lt;/div&gt;
      &lt;div class="span6"&gt;
          &lt;ul class="thumbnails"&gt;
              &lt;li class="span6"&gt;
                  &lt;div class="thumbnail"&gt;
                      &lt;img src="http://placehold.it/150x100" /&gt;
                  &lt;/div&gt;
              &lt;/li&gt;    
              &lt;li class="span6"&gt;
                  &lt;div class="thumbnail"&gt;
                      &lt;img src="http://placehold.it/150x100" /&gt;
                  &lt;/div&gt;
              &lt;/li&gt;    
              &lt;li class="span6"&gt;
                  &lt;div class="thumbnail"&gt;
                      &lt;img src="http://placehold.it/150x100" /&gt;
                  &lt;/div&gt;
              &lt;/li&gt;    
          &lt;/ul&gt;
      &lt;/div&gt;
  &lt;/div&gt;
  </code></pre>