title: Django model iterate fields
body: <p>how can I iterate and retrieve all fields of a django model?</p>
  
  <p>I know that <code>foo.item._meta.get_all_field_names()</code> brings me all field names.
  How can I access those fields (incl. their actual values) on a model instance? (Except the normal notation <code>foo.fieldname</code>).</p>
  
  <p>I need this in order to build a custom output for my model including its manyTomany relations.
  Any ideas?</p>