Supply the DB_FORWARDONLY option on ODBC snapshots

Recordset objects of the Snapshot type provide bi-directional scrolling capability by default. If you only need to make a single pass through the records of a Snapshot, you can Or the DB_FORWARDONLY flag with any other existing flag in OpenRecordset()'s intOptions argument. This makes the Snapshot more efficient, because the result set is not copied to a scrollable buffer area.