apply()/unpack(): new simpler implementation
apply()/unpack(): new simpler implementation

This will hopefully also compile cleanly with clang on MacOSX...

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