A data structure for segmentations.

• Two possible segmentation representations -> image or contour based.
• DICOM conformity (DICOM RT for contour based segmentation / DICOM Segmentation Objects).
• Support undo/redo functionality.
• Save/Load Segmentation -> own file structure and type.
• Extensible with multi-label segmentation.
• Conversion between contour based and image based segmentation