Respect Tablefield's "Hide table header row" field setting.

modules/d3_sankey_table_group_pp/d3_sankey_table_group_pp.module

@@ -228,6 +228,14 @@ function d3_sankey_table_group_pp_field_formatter_view($entity_type, $entity, $f
   // the table grouping preprocessor.
   if ($display['type'] === 'tablefield_d3_sankey_table_group_pp') {
     foreach ($items as $delta => $item) {
+      // For convenience / clarity, make a copy of the rows we are to display.
+      // Then, if the field settings say to hide the first row, unset it from
+      // our copy.
+      $rows = $item['tabledata'];
+      if ($field['settings']['hide_headers']) {
+        unset($rows[0]);
+      }
+
       // Apply the formatter settings to the chart.
       $chart = array(
         'sankeyType' => (string) $settings['sankeyType'],
@@ -267,7 +275,7 @@ function d3_sankey_table_group_pp_field_formatter_view($entity_type, $entity, $f
       // Initialize a GroupingPreprocessor, feed it the query results, get the
       // raw data out of the preprocessor, and add it to the chart.
       $preprocessor = new TableGroupingPreprocessor();
-      foreach ($item['tabledata'] as $row) {
+      foreach ($rows as $row) {
         $preprocessor->ingestRow((array) $row);
       }
       $raw_data = $preprocessor->getRawData();