This test verifies that ascii grids are imported correctly.
Joaquim Luis discovered that ANUGA misinterpreted the xllcorner and yllcorner 
parameters and devised this test to reveal the problem. See sourceforge mailing thread: http://sourceforge.net/mailarchive/forum.php?thread_name=4727D555.7010208%40ualg.pt&forum_name=anuga-user

For testing purposes, the script was modified with use_cache=False.

The error manifests itself when the dem (sub_region.asc, sub_region.prj) and the polygons (shallow.csv, out_rect.csv) in turned into a domain and the boundary condition defined in br_swan.sww is applied. With wrong pixel registration, the domain will be out by 0.5*cellsize and therefor outside the area covered by 
the boundary condition.

--
It turned out that this test didn't reveal the registration problem after all
(see sourceforge postings Nov 2007), but rather that ANUGA didn't 
give a proper error if the domain exceeds the boundary defined in Field_boundary.

We don't want to raise an Exception, but the code now has appropriate warnings.
This directory is therefore not really part of the validation suite after all.