- implement more specializations of BinaryAttributeOpeningImageFilter
- implement more specializations of LabelAttributeOpeningImageFilter
- implement more specializations of AttributeRelabelImageFilter
- implement more specializations of BinaryAttributeKeepNObjectsImageFilter
- implement more specializations of LabelAttributeKeepNObjectsImageFilter
- implement more shape descriptors
- implement some statistic descriptors
- reimplement LabelShapeImageFilter (http://voxel.jouy.inra.fr/darcsweb/darcsweb.cgi?r=labelShape;a=summary) with the new classes
- perhaps, reimplement LabelStatisticsImageFilter with the new classes