iFit/calculate_q_bins

 Calculate qh,qk,ql,en for the centres of the bins of a d2d dataset

   >> [q,en]=calculate_q_bins(win)

 Input:
 ------
   win     Input d2d dataset

 Output:
 -------
   q       Components of momentum (in rlu) for each bin in the dataset for a single energy bin
           Arrays are packaged as cell array of column vectors for convenience
           with fitting routines etc.
               i.e. q{1}=qh, q{2}=qk, q{3}=ql
   en      Column vector of energy bin centres. If energy was an integration axis, then returns the
           centre of the energy integration range