Ecospace throws an Exception after maps have been re-sized

[joeb]

1. Open an Ecospace scenario with a large number of cells.
2. Define a migration pattern for one of the groups that uses the outside edge of the map.
3. Save the scenario.
4. Resize the map to smaller size so that the migration pattern is outside the map for at least part of the map.
5. Run Ecospace
6. Ecospace will assert on an Exception in cEcopace.SetMigGrad?() then keep running

The PrefRow?() and PrefCol?() arrays will/can contain row and col indexes outside the map boundary. This may also happen with Habitats, I haven't checked this. Try assigning a group to the last habitat type, then save delete the habitat and see if Ecospace will run.