When dialogs RoiStat3D and RoiStat4D are acivated, the "ROI is empty" error message is displayed,  show the name of the ROI layer.

Added the progress indicator to the FireVoxel document load. This is very helpful when loading very large volumes (such as PET)

Fixed an error writing incorrect datatype in ANALYZE 7.5 format (for 16-bit volume)