update Viewer to allow for is_wireframe in no data case
update Viewer to allow for is_wireframe in no data case

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