tckmap: Revert to full calculation when using DEC and voxel-wise mean
tckmap: Revert to full calculation when using DEC and voxel-wise mean

MRtrix3/mrtrix3,MRtrix3/mrtrix3,MRtrix3/mrtrix3,MRtrix3/mrtrix3,MRtrix3/mrtrix3,MRtrix3/mrtrix3