linearizer: extractor.py: new --linearization option
linearizer: extractor.py: new --linearization option

- support linearization when dumping to VTK
- new create_problem(), parse_linearization()
- update main()

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