Adding classes to table cells for easier theming with css

This is a feature request with patch for an enhancement where the cells of the tableselect are all classed with their column names (if keyed) or numerical indexes (when not keyed).

It supports the header being defined as either:

$header = array('one', 'two', 'three'); //or
$header = array(array('data'=> 'one','class'=>'some-class'),array('data'=>'two'),array('data'=>'three'));

I'm using this on drupal 6, and it's making my life theming table selects much easier.

Will attach the patch shortly.