Fixed defects of Automatic WM brain seed detection.  Procedure was producing wildly incorrect results in case if some VOIDVOX values were present in the volume.

Some suspicious voxels present in brain image

Implementing a new UI-level function:
User Loads 4D volume + organ ROI.
One or more input functions corresponding to separate blood vessels
are loaded.
Function executes and the result is the Map of the blood vessels inside the
organ.