OpCarving: Provide OutputSlot for MstOut, which is a cached version of the MST for downstream applets.
OpSplitBodyCarving: Provide OutputSlot for edited raveler body list.
OpSelectLabel: Provide the selected label as metadata.
SplitBodyPostprocessing: Implemented post-processing for each body.  Still need to aggregate into a final image.
SplitBodyPostprocessing: Implemented final segmentation slot.