Lung segmentation boundary filtering issue

[haribalankumar]

Current PTK lung segmentation assigns ROI labels 1 and 2 (for left and right lungs)
This is inconsistent with PASS which uses 5 and 17.

Also lung segmentation has a smeared boundary
(ie) near boundary of 200 ROI for example, there are some 150s , 100s, 60s and finally goes to background 0. As these are very small voxels, they can be filtered out easily. But this feature is missing.