pgsql fixes and improvements are in 8.0 and 8.1

I've been running a large regression-suite-test here locally on the pgsql driver. Out came some problems in the case of multiple statements running on the same connection in parallel raising one or more errors. The driver sometimes got out of sync with the database because they did not agree on which of the multiple running statements needed to be canceled early.

These issues have been fixed. Regression tests now show zero problems.

I'm running both 8.1: 66d6ffe9de148d15a4d52e25f23a66d81e98e0f8 and 8.0: 83a8fde6fd9d74a7f35361390fe4e3c1ad9d77ea on all my production systems as of now.

Anyone using PostgreSQL with Pike is invited to test as well.