Substantially sped up huffman decompression, by replacing the bit-testing loop for all codes under 12-bit long. Instead a direct table is used which covers bulk of the codes, but is still small in size.
This allowed to speed up decompression by x3 times. This is extremely important,  because when user draws an ROI over signal intensity volume, a lag will appear in the ROI drawing if the decompression is not fast enough.