- ad_image.module

    o put more information about the image ad into the $node array
 - ad_text.module
    o put more information about the text ad into the $node array
 - ad.module
    o track the HTTP_USER_AGENT on ad clicks (to allow filtering clicks
      generated by bots that report themselves as bots)
 - ad.install
    o add user_agent column to ad_clicks table for tracking user agents