iFit/minus

 Implement w1 - w2 for objects

   >> w = w1 - w2

   if w1, w2 are objects of the same size:
       - the operation is performed element-by-element

   if one of w1 or w2 is numeric:
       - if a scalar, apply to each element of the object numeric array
       - if an array of the same size as the object numeric array, apply
        element by element

   w1, w2 can be arrays:
       - if objects have same array sizes, then add element-by-element
       - if an (n+m)-dimensional array, the inner n dimensions will be
        combined element by element with the object numeric array (where
        n is the dimensionality of the object numeric array), and the
        outer m dimensions must match the array size of the array of objects
%   Overloaded methods:
      sqw/minus
      testsigvar/minus
      sigvar/minus
      IX_dataset_3d/minus
      IX_dataset_2d/minus
      IX_dataset_1d/minus
      sqw/minus
      sigvar/minus
      d4d/minus
      d3d/minus
      d2d/minus
      d1d/minus
      d0d/minus
      codistributed/minus
      gpuArray/minus
      timeseries/minus
%   Reference page in Help browser
      doc minus