correct sfepy/fem/meshio.py since MED node groups are actually positive
correct sfepy/fem/meshio.py since MED node groups are actually positive

vlukes/sfepy,sfepy/sfepy,lokik/sfepy,sfepy/sfepy,rc/sfepy,RexFuzzle/sfepy,olivierverdier/sfepy,RexFuzzle/sfepy,olivierverdier/sfepy,olivierverdier/sfepy,sfepy/sfepy,rc/sfepy,BubuLK/sfepy,rc/sfepy,RexFuzzle/sfepy,lokik/sfepy,lokik/sfepy,lokik/sfepy,BubuLK/sfepy,RexFuzzle/sfepy,vlukes/sfepy,BubuLK/sfepy,vlukes/sfepy