fix contiguousness of mtx_i
fix contiguousness of mtx_i

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