Enabling module causes blank lines in the navigation block

Confirmed, I think that requires some tweaking in the menu_alter hook.

      $items[$menu_path] = array(
        'page callback' => 'restws_page_callback',
        'page arguments' => array($resource),
        'access callback' => TRUE,
      );

You are missing 'type' => MENU_CALLBACK,.

fago fixed that recently.

The first code chunk (line 161 of restws.module) is still missing its type declaration.

Thanks, fixed.