title: what is the difference between the functions getAddUrl and getAddToCartUrl?
body: <p>I have found two function returning the exactly same value.</p>
  
  <p><code>getAddUrl</code> in <code>\app\code\local\Mage\Checkout\Helper\Cart.php</code></p>
  
  <p><code>getAddToCartUrl</code> in <code>\app\code\local\Mage\Catalog\Block\Product\Abstract.php</code></p>
  
  <p>what is really the difference between these two?as I am adding an add to cart button in my block.
  Which function should I use?</p>