Import MunkRes module error 

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ERROR: test_ward_spatial_cmd (pyhrf.test.test_parcellation.CmdParcellationTest)
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Traceback (most recent call last):
  File "/volatile/ciuciu/pyhrf/python/pyhrf/test/test_parcellation.py", line 237, in test_ward_spatial_cmd
    dist = parcellation_dist(self.p1, labels)[0]
  File "/volatile/ciuciu/pyhrf/python/pyhrf/parcellation.py", line 998, in parcellation_dist
    from munkres import Munkres
ImportError: No module named munkres

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ERROR: test_ward_spatial_scikit (pyhrf.test.test_parcellation.ParcellationMethodTest)
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Traceback (most recent call last):
  File "/volatile/ciuciu/pyhrf/python/pyhrf/test/test_parcellation.py", line 158, in test_ward_spatial_scikit
    dist = parcellation_dist(self.p1+1, labels+1)[0] #+1 because parcellation_dist sees 0 as background
  File "/volatile/ciuciu/pyhrf/python/pyhrf/parcellation.py", line 998, in parcellation_dist
    from munkres import Munkres
ImportError: No module named munkres

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ERROR: test_ward_spatial_scikit_with_mask (pyhrf.test.test_parcellation.ParcellationMethodTest)
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Traceback (most recent call last):
  File "/volatile/ciuciu/pyhrf/python/pyhrf/test/test_parcellation.py", line 188, in test_ward_spatial_scikit_with_mask
    dist = parcellation_dist(self.p1+1, labels+1)[0]
  File "/volatile/ciuciu/pyhrf/python/pyhrf/parcellation.py", line 998, in parcellation_dist
    from munkres import Munkres
ImportError: No module named munkres