fix checking of term - integral compatibility
fix checking of term - integral compatibility

- update Term.from_desc(), .__init__(), .set_integral()

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