Build 381 is released.

 1. Fixed important crash defect in IsVoidVoxPresent function.

2. Modified the optional REAL loseless compression scheme getting x2-x4 compression on real PET images.

3. Reimplemented Huffman compression API for 1-byte value buffers.

4. Updated internal lossless compression for REAL images:

PET image with 60 timepoints, 400 MB of data is LOSSLESSLY

compressed down to about 50MB (x8 compression). This compression is optional (managed through UI Options dialog), only slightly slower. Also would reduce the size of the FVX file if saved.

5. Code optimization for internal compression of ROIs, somewhat higher speed possibly will be noticeable while drawing on ROIs on slower computers.

6. Pancreas axis segmentation: added the centerline length info to the output and the Clipboard Output.