set_smearer draw model again if smearer different of None
set_smearer draw model again if smearer different of None

lewisodriscoll/sasview,lewisodriscoll/sasview,SasView/sasview,lewisodriscoll/sasview,lewisodriscoll/sasview,SasView/sasview,SasView/sasview,SasView/sasview,lewisodriscoll/sasview,SasView/sasview,SasView/sasview