set ts directly in ProblemDefinition.update_time_stepper()
set ts directly in ProblemDefinition.update_time_stepper()

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