Expose the currency code widget setting

I noticed that commerce_price_table_field_widget_form() copies parts of commerce_price_field_widget_form(), but not the part for the currency_code field. This makes commerce_price_table unable to work in a multi-currency environment.

Why not just take the element created by commerce_price_field_widget_form() and add the additional fields for min_qty and max_qty to it? This results in a much smaller widget form function, and as far as I see multi currency support works out of the box:

/**   
 * Implements hook_field_widget_form().
 */ 
function commerce_price_table_field_widget_form(&$form, &$form_state, $field, $instance, $langcode, $items, $delta, $element) {
  if ($instance['widget']['type'] == 'commerce_price_table_multiple') {
    // Get a standard widget field from module 'price'.
    $priceInstance = $instance;
    $priceInstance['widget']['type'] = 'commerce_price_full';
    $element = commerce_price_field_widget_form($form, $form_state, $field, $priceInstance, $langcode, $items, $delta, $element);

    // Replace validator and add commerce_price_table styles.
    $element['#element_validate'] = array('commerce_price_table_field_widget_validate');
    $element['#attached']['css'][] = drupal_get_path('module', 'commerce_price_table') . '/theme/commerce_price_table.css';
    
    // Add our own fields.
    $element['min_qty'] = array(
      '#type' => 'textfield',
      '#title' => t('Min Qty'),
      '#description' => t('Minimum quantity for the price range.'),
      '#default_value' => isset($items[$delta]['min_qty']) ? $items[$delta]['min_qty'] : 0,
      '#size' => 10,
    );
    $element['max_qty'] = array(
      '#type' => 'textfield',
      '#title' => t('Max Qty'),
      '#description' => t('Maximum quantity for the price range. Use "-1" for unlimited quantity.'),
      '#default_value' => isset($items[$delta]['max_qty']) ? $items[$delta]['max_qty'] : 0,
      '#size' => 10,
    );
  }

  return $element;
}