Enhance the OP_OpenDup opcode of the bytecode engine so that it works even if the cursor being duplicated itself came from OP_OpenDup.

When materializing correlated common table expressions, do so separately for each use case, as that is required for correctness.

Improvements to error messages generated by faulty common table expressions.

Fix to the SELECT statement syntax diagram so that the FROM clause syntax is shown correctly.

Improvements the xBestIndex method in the implementation of the wholenumber virtual table extension so that it does a better job of convincing the query planner to avoid trying to materialize a table with an infinite number of rows.