Idle In Transaction Session Timeout, revived

Attached is a rebased and revised version of my
idle_in_transaction_session_timeout patch from last year.

This version does not suffer the problems the old one did where it would
jump out of SSL code thanks to Andres' patch in commit
4f85fde8eb860f263384fffdca660e16e77c7f76.

The basic idea is if a session remains idle in a transaction for longer
than the configured time, that connection will be dropped thus releasing
the connection slot and any locks that may have been held by the broken
client.

Added to the March commitfest.
--
Vik Fearing                                          +33 6 46 75 15 36
http://2ndQuadrant.fr     PostgreSQL : Expertise, Formation et Support