title: get magento module config data in Observer
body: <p>I created a module with an observer for the sales module with event hook ‘sales_order_shipment_save_after’ ,</p>
  
  <p>My module has the following files</p>
  
  <ol>
  <li>Company/Modulename/etc/config.xml</li>
  <li>Company/Modulename/etc/system.xml</li>
  <li>Company/Modulename/Model/Observer.php</li>
  </ol>
  
  <p>there are four fields in the modules admin configuration fields
  I want to get those saved data in the Observer class.</p>
  
  <p>using <strong>$this->getConfigData(’password’);</strong> gives a</p>
  
  <blockquote>
    <p>Call to undefined method</p>
  </blockquote>
  
  <p>error
  Any suggestions? </p>