Switched default to non-ideal positioning of PXL volumes (currently this affects active layers only). The change assumes that the user runs StPxlDbMaker to create the dataset with appropriate transformations
StiDetector: Added splitIt method to split this volume along the radial direction. Also added a missing assignment for StiElossCalculator in copy
StiDetectorBuilder: Added parameters defining the volume splitting procedure and a call to the splitting routine based on these parameters