title: disable ordering by default for django_tables2 Tables
body: <p>I use <a href="http://django-tables2.readthedocs.io/en/latest/" rel="noreferrer">django_tables2</a> to render my tables. For one table, I only want to see the most recent 5 entries. Therefore, I need to order my queryset before passing it to the table object:</p>
  
  <pre><code>qset = myObject.objects.order_by('-start_time').all()[:5]
  table = MyTableClass(qset, template='path/to/template.html')
  </code></pre>
  
  <p>This yields the following error message:</p>
  
  <pre><code>AssertionError: Cannot reorder a query once a slice has been taken.
  </code></pre>
  
  <p>I could set <code>orderable=False</code> for every <code>django_tables.Column</code>, but since MyTableClass inherits from another table class, I would like to avoid this.</p>
  
  <p>Thanks in advance</p>