fixelcfestats: Avoid use of make_shared due to memory alignment
fixelcfestats: Avoid use of make_shared due to memory alignment

See #957.

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