move set_constant() to Variable
move set_constant() to Variable

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