pairlist.h: clean up
pairlist.h: clean up

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