fix for shader editor example crash when editing on python 2
fix for shader editor example crash when editing on python 2

rnixx/kivy,bionoid/kivy,darkopevec/kivy,aron-bordin/kivy,jegger/kivy,janssen/kivy,akshayaurora/kivy,jegger/kivy,janssen/kivy,KeyWeeUsr/kivy,rafalo1333/kivy,aron-bordin/kivy,kived/kivy,jegger/kivy,bionoid/kivy,matham/kivy,bionoid/kivy,kived/kivy,tony/kivy,el-ethan/kivy,andnovar/kivy,autosportlabs/kivy,andnovar/kivy,aron-bordin/kivy,KeyWeeUsr/kivy,aron-bordin/kivy,bionoid/kivy,el-ethan/kivy,manthansharma/kivy,matham/kivy,Cheaterman/kivy,manthansharma/kivy,rafalo1333/kivy,jegger/kivy,akshayaurora/kivy,andnovar/kivy,LogicalDash/kivy,tony/kivy,KeyWeeUsr/kivy,rnixx/kivy,jkankiewicz/kivy,inclement/kivy,LogicalDash/kivy,janssen/kivy,Cheaterman/kivy,janssen/kivy,darkopevec/kivy,jkankiewicz/kivy,Cheaterman/kivy,inclement/kivy,el-ethan/kivy,rnixx/kivy,autosportlabs/kivy,akshayaurora/kivy,jkankiewicz/kivy,jkankiewicz/kivy,kived/kivy,matham/kivy,manthansharma/kivy,tony/kivy,LogicalDash/kivy,inclement/kivy,KeyWeeUsr/kivy,rafalo1333/kivy,darkopevec/kivy,Cheaterman/kivy,autosportlabs/kivy,matham/kivy,LogicalDash/kivy,kivy/kivy,kivy/kivy,manthansharma/kivy,darkopevec/kivy,kivy/kivy