The prefixes list table class.
See http://codex.wordpress.org/Class_Reference/WP_List_Table and http://wpengineer.com/2426/wp_list_table-a-step-by-step-guide/
$_column_headers :
get_columns()
prepare_items()
column_default( $item, $column_name)
column_prefix( $item)
column_cb( $item)
get_sortable_columns()
usort_reorder( $a, $b)
get_bulk_actions()