Allow DS to render block templates with inherited contextual links

When creating fields using hook_ds_fields_info(), take for example:

  $fields['my_view_block'] = array(
    'title' => t('My View Block'),
    'field_type' => DS_FIELD_TYPE_BLOCK,
    'ui_limit' => array('user|full'),
    'properties' => array(
      'block' => 'views|my_view-block_1',
      'block_render' => DS_BLOCK_TEMPLATE,
    ),
  );

The field does render the block with the contextual links, but it loses the view's contextual links (ie: "Edit view"). This patch allows the field to render the block with any inherited contextual links that were generated by the hook_block_view() call.