Author: Marin Stavrev <mstavrev@gmail.com>

Author: Marin Stavrev <mstavrev@gmail.com>
ZPH (Zero Penalty Hit) QOS features.

Adds --enable-zph-qos options to turn on the following:

 - Allows you to select a TOS/Diffserv value to mark local hits.

 - Allows you to select a TOS/Diffserv value to mark peer hits.

 - Allows you to selectively set only sibling or sibling+parent requests

 - Allows any HTTP response towards clients will
   have the TOS value of the response comming from the remote
   server masked with the value of zph_preserve_miss_tos_mask.
   For this to work correctly, you will need to patch your linux
   kernel with the TOS preserving ZPH patch.
   The kernel patch can be downloaded from http://zph.bratcheda.org

 - Allows you to mask certain bits in the TOS received from the
   remote server, before copying the value to the TOS send towards
   clients.