Add option not to cache the whole resultset on the client, but fetch it row by row

This can help reduce memory required on the big resultsets. If selected, this option will not force use of forward-only cursors, i.e. "force use of of forward only cursor" won't get automatically selected, but result streaming will be used for those statements, for which forward-only cursor type is set. In this way streaming will be possible to use not for all query results - user will have control over that.