o bug #417512: use proper variable names in emails
 - ad_token.inc
    o bug #417512: (renamed from token_ad.inc to match the ad module's naming
      standards) cleanup logic to always return a value even if 0, remove
      nonexistent this_week_impressions and this_week_clicks variables
 - ad_token.install
    o bug #417512: replace old variables with new variables in already
      existing notifications

    o bug #406278: fix PHP E_ALL notices
      (fix includes patch by Garrett Albright)
 - ad_cache_file.module
    o fix PHP E_ALL notices
 - token_ad.inc
    o fix PHP E_ALL notices