A persistent multi-version map: avoid 'magic' casting in the comparator, because strictly Collections.binarySearch could swap the parameter objects in the call to the compare method. This should also simplify porting the code to C.

(a) any accidental further access to it
(b) throwing an exception if the client code calls close() more than once

Fix for a bug where we would sometimes use the wrong unique constraint to validate foreign key constraints.

Stand-alone command line version of the profiling tool (will be merged with the profiling tool later on).

PostgreSQL compatibility: support for EXTRACT(WEEK FROM dateColumn). Thanks to Prashant Bhat for the patch!

PostgreSQL compatibility: support for EXTRACT(WEEK FROM dateColumn). Thanks to Prashant Bhat for the patch!