title: django-tables2: Table.render_Foo naming
body: <p>I got the following Table and want to implement a <code>render_foo()</code> function for the <code>modelField.ST</code> and <code>modelField.ZF</code> fields. </p>
  
  <pre><code>class MyTable(Table):
      class Meta:
          model = MyModel
          fields = ('modelField.ST', 'modelField.ZF', 'score')
  </code></pre>
  
  <p>How are they named?</p>
  
  <p><code>def render_modelField_ST(self, record)</code></p>
  
  <p>and </p>
  
  <p><code>def render_modelField__ST(self, record)</code></p>
  
  <p>did not work</p>
  
  <p>Thank you!</p>