auto_whitelist()
  Whitelist IP addresses after sending some emails properly.
  This whitelisting is done not more than every 10 minutes to avoid server
  overload. This function is slow for large number of records, use it
  carefully.
  
  Usage: auto_whitelist(match_count=10, table='greylist')
  
  Where: match_count is number of record which will must match
         table can define table alternative
  
  Example: auto_whitelist(10)
  
  New in version 0.8.0.