clean up BernsteinTensorProductPolySpace._eval_base()
clean up BernsteinTensorProductPolySpace._eval_base()

rc/sfepy,rc/sfepy,BubuLK/sfepy,vlukes/sfepy,sfepy/sfepy,sfepy/sfepy,BubuLK/sfepy,sfepy/sfepy,vlukes/sfepy,BubuLK/sfepy,rc/sfepy,vlukes/sfepy