Client bandwidth limits for squid3-trunk

Hi all,
   I am working on adding support for client-side bandwith limiting on
squid3. The related description of this feature is at
http://wiki.squid-cache.org/Features/ClientBandwidthLimit

The feature implemented by Alex Rousskov for his 3p1-rock branch. In
this mail I am including a first port for squid-trunk.

The patch needs more testing and probably farther development but I am
posting the current patch for preview and initial feedback.

A short description included in the patch.

Regards,
     Christos