Fixed a problem with simplification of levels, where it was possible for empty GeometryCollections to be added to a GeometryCollection, which throws an exception.
Fixed a problem with simplification of levels, where it was possible for empty GeometryCollections to be added to a GeometryCollection, which throws an exception.

JimCallahanOrlando/DistrictBuilder,JimCallahanOrlando/DistrictBuilder,JimCallahanOrlando/DistrictBuilder,JimCallahanOrlando/DistrictBuilder