improved error handling from Victor
improved error handling from Victor

richardjgowers/csg,votca/csg,MrTheodor/csg,MrTheodor/csg,junghans/csg,richardjgowers/csg,junghans/csg,votca/csg,votca/csg,richardjgowers/csg,junghans/csg,MrTheodor/csg,junghans/csg,votca/csg,richardjgowers/csg,richardjgowers/csg,MrTheodor/csg,junghans/csg,MrTheodor/csg,junghans/csg