new dict_from_options(), update ProblemConf.from_file_and_options()
new dict_from_options(), update ProblemConf.from_file_and_options()

- make dict_from_string a standalone function
- update ProblemConf.from_file()

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