update Equations.evaluate() - split weak branch, fix/update docstring
update Equations.evaluate() - split weak branch, fix/update docstring

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