Fixed the layering for WITH LOCK and (partially) ANY/ALL predicates.
Cleaned up the outdated code that never worked (mapping DISTINCT to an index, some VMS remainings).
Wiped out a lot of the pre-ODS11 optimizer logic. Some minor adjustments there.
Re-implemented the full outer join from scratch. This resolves CORE-2678 (full outer join cannot use available indices).
Resolved CORE-2796: DB_KEY is always zero for external tables.
Implemented the core part of the scrollable PSQL cursors. Implementation is still incomplete, but ready for testing.
Some other changes I don't recall at the moment ;-)
WARNING! The engine may be unstable. Please email me about any issues found.
