.travis.yml: don't build gromacs for MINIMAL
.travis.yml: don't build gromacs for MINIMAL

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