Support for header fields

theme_table supports cells having a 'header' key along-side a 'data' key to designate that the cell is a header cell. Trying this with table field, however, causes the array containing the 'header' and 'data' fields to be wrapped in another array, with a key of data.

For example:

BEFORE Table Field Processing

$table['rows'] = array(
  array(
     array(
       'data' => t('First header on the first row'),
       'header' => TRUE,
     ),

     t('First value on the first row'),
  ),

  array(
     array(
       'data' => t('First header on the second row'),
       'header' => TRUE,
     ),

     t('First value on the second row'),
  ),
);

AFTER Table Field Processing

$table['#rows'] = array(
  0 => array(
     'data' => array(
       0 => array(
         'data' => array(
           'data' => t('First header on the first row'),
           'header' => TRUE,
         ),

        1 => array(
          'data' => t('First value on the first row'),
     ),
  ),
  1 => array(
     'data' => array(
       0 => array(
         'data' => array(
           'data' => t('First header on the second row'),
           'header' => TRUE,
         ),

        1 => array(
          'data' => t('First value on the second row'),
     ),
  ),
);