dwidenoise: polymorphic data type handling
dwidenoise: polymorphic data type handling

With this commit, the complex (magnitude-phase) input data will be processed with complex computations, whereas real input data will select an optimized code branch for real data. This is a significant performance gain w.r.t. treating everything as complex.

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