easier_terms: update examples/biot/biot_npbc.py for new Term.evaluate()
easier_terms: update examples/biot/biot_npbc.py for new Term.evaluate()

- it seems to work!

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