BaseData - Rebuild patial index after exclusions are run

[GoogleCodeExporter]

What steps will reproduce the problem?
1.  Run exclusions on a BaseData object
2.  Try to run a spatial analysis that needs neighbours (so it uses the spatial 
index).
3.  It will fail because an element does not exist.

Rebuilding the spatial index fixes this issue, but the process should be 
applied automatically when exclusions are run (and groups were deleted).

Original issue reported on code.google.com by shawnlaffan on 1 Oct 2010 at 1:42