1.1.5 -> 1.1.6
  * added reqdeny / reqallow rules
  * added HTTP 400 and 403 responses
  * chain regex in a list
  * reply 502 when no server is available
1.1.6 -> 1.1.7
  * implement global logging
  * have a single log function
  * add x-forwarded-for
  * log http requests on demand, and destination server name
1.1.7 -> 1.1.8
  * full HTTP log with destination server ID, req and resp time.
  * source address of outgoing connections
1.1.8 -> 1.1.9
1.1.9 -> 1.1.10
  * automatically remove client cookie in insert+indirect mode
1.1.10 -> 1.1.11
  * support multi-cookie as described in RFC2109
  * added "nocache" option to prevent caches from storing cookies.