- Inserting NULL into a primary key + foreign key column

- Inserting NULL into a primary key + foreign key column
will allow the "not null constraint" error to raise,
not an attempt to execute a nonexistent "col_id_seq"
sequence.  [ticket:1516]

- autoincrement SELECT statements, i.e. those which
select from a procedure that modifies rows, now work
with server-side cursor mode (the named cursor isn't
used for such statements.)