Handle SET TRANSACTION ISOLATION LEVEL. Get a warning if not trying to set to SERIALIZABLE, but no error.
Allow setting money locale.
Only give warning once.
Extend test.
Ignore unlisten statement, somewhat generally and somewhat efficiently.
merge MMcM: More npgsql compatibility in the PG server

Merge pull request #1025 from MMcM/sql-layer/pg-more-npgsql
https://github.com/FoundationDB/sql-layer/pull/1025