Bug 3236: Port of %oa, %<lp and %<la log format options

Bug 3236: Port of %oa, %<lp and %<la log format options

Christos Tsantilas:
 Add logging of the local TCP port used by transactions with http servers

  The new log format code is "%<lp"

  In the case there are several server-side connections logs the port of
  the last connection.

  This is a Measurement Factory project.

Amos Jeffries:
 Port 2.7: logformat tag for logging the outgoing IP address (tcp_outgoing_address)

  This adds the log format to log the local IP address used on outgoing
  connections to peers and servers. Squid-2.7 called this %oa.

  However it is a perfectly matching part of the existing set of %la and
  %lp (local inbound) and %<lp (local outbound port).

  As such, the %oa is accepted as input for backward compatibility, but the
  Squid-3 version is: %<la

  This is based only very loosely on the Squid-2 %oa work by Andrew Atangulov