Slow performance when rendering layers with null geometries

[ronnielouie]

When stylizing geometries, null check was purposely ommited because it was believed to incur additional overhead to check for null before retrieving the geometry. Geometry value generally should not be null, but there is no guarantee of this. If a null does occur, it is handled by catching the exception and ignoring it which actually slows down the reading of the data.

[ronnielouie]

Adding null check provides significant performance improvement, without much impact for the normal case when there are not any nulls.  http://trac.osgeo.org/mapguide/changeset/3142