This patch ticks off the following TODO items:
* Add session start time and last statement time to pg_stat_activity
(we already had last-statement-time, provided command string stats were
enabled)
* Add the client IP address and port to pg_stat_activity
I have tested on Linux (both IPV4 and Unix sockets for the address/port)
and Win32 (naturally only IPV4). I don't have a machine around with IPV6
support, so I haven't tested that. The code to handle it is stolen from
inet_client_addr() though, so it should hopefully be ok.
//Magnus
