COL_REARRANGE - reorders a matrix using a clustering result
    [A, N_COLS, COL_INDS]=COL_REARRANGE(A, CLUSTERS) reorders 
    the columns of matrix A using the clustering result represented 
    by the structure CLUSTERS. N_COLS stores the last column index 
    for each column block, while COL_INDS containes the permuted 
    column indices.
 
  Copyright 2011 Dimitrios Zeimpekis, Eugenia Maria Kontopoulou, 
                 Efstratios Gallopoulos