Need to add _content function to fix filters

The following function needs to be added:

function product_content($node, $main = 0) {
  return node_prepare($node, $main);
}

As well, above line 28, the following code is needed:

  $node = product_content($node, $main);
  return theme("node", $node, $main, $page); // line 28

This makes sure that filters are applied. Without it, the image filter (among others) won't work.