Bug fix: didn't initialize the TextureOpt::envlayout field in default ctr.
Bug fix: didn't initialize the TextureOpt::envlayout field in default ctr.

micler/oiio,mcanthony/oiio,sambler/oiio,lgritz/oiio,scott-wilson/oiio,mcanthony/oiio,OpenImageIO/oiio,sambler/oiio,micler/oiio,cwilling/oiio,jeremyselan/oiio,cwilling/oiio,lgritz/oiio,bdeluca/oiio,jeremyselan/oiio,OpenImageIO/oiio,OpenImageIO/oiio,lgritz/oiio,mcanthony/oiio,bdeluca/oiio,micler/oiio,YangYangTL/oiio,scott-wilson/oiio,sambler/oiio,YangYangTL/oiio,micler/oiio,cwilling/oiio,lgritz/oiio,jeremyselan/oiio,YangYangTL/oiio,bdeluca/oiio,bdeluca/oiio,OpenImageIO/oiio,YangYangTL/oiio,mcanthony/oiio,sambler/oiio,scott-wilson/oiio,scott-wilson/oiio,cwilling/oiio