Fixed csvexport to write in primary key order.

Good news: This no longer relies on InnoDB's default row order.

Bad news: InnoDB in MySQL 5.0 has a bug where it will sort rows
physically according to a secondary index, if there's a composite
primary key and a single-column index and the phase of the moon is
right.  So a couple tables have been, once again, reordered -- but
correctly this time.

Good news: This bug will no longer fuck me up!