Bug #2459 fix, access logging enhancements, ICAP logging and retries support:

Bug #2459 fix, access logging enhancements, ICAP logging and retries support:

  - Bug #2459 fix

  - Support logging of total DNS wait time to access.log
    (%dt)

  - Support logging response times of adaptation transactions to access.log
    (%adapt::sum_trs and %adapt::all_trs)

  - Enhanced access logging
    (<Hs, <sh, >sh, <pt, <tt, icap::tt, and icap::<last_h in squid.conf)

  - ICAP logging
    (see icap_log and log_icap in squid.conf as well as
    http://wiki.squid-cache.org/Features/AdaptationLog).

  - ICAP retries based on the ICAP responses status code
    (see icap_retry_limit in squid.conf).

Merged from 3p1-plus branch at r9511.