fix eval mode in ExpressionBuilder.build()
fix eval mode in ExpressionBuilder.build()

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