Updates INSTALL.txt to reflect changes for Webform 3.x support.

INSTALL.txt

@@ -31,23 +31,6 @@ Installation
 
 4. Create or edit a webform that you would like to have users submit a payment for.
 
-   Under 'Webform Advanced Settings', add the following code for 'Additional Validation', with
-   the leading space removed before the <?php line:
-   
-	<?php
-	  require_once(drupal_get_path('module', 'authorizenetwebform') . '/authorizenetwebform.module');
-	  $form_state = authorizenetwebform_process("validate", $node, $form_id, $form_state);
-	?>
-
-   Then, in the 'Additional Processing' box, add the following code, again removing the leading
-   space removed before the <?php line:
-
-	<?php
-	  require_once(drupal_get_path('module', 'authorizenetwebform') . '/authorizenetwebform.module');
-	  $form_state = authorizenetwebform_process("submit", $node, $form_id, $form_state);
-	?>
-
-
    For each component added, you may select a Authorize.Net field to map to.  The required fields
    are listed for easy mapping.  Custom fields must be entered into the "Administer" ->
    "Site Configuration" -> "Authorize.Net Payment Webform" screen.