fix/update semi-smooth Newton solver
fix/update semi-smooth Newton solver

- it runs with test_semismooth_newton.py, but does not converge well

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