multi_g_rdf: reworked --help
multi_g_rdf: reworked --help

Pallavi-Banerjee21/votca.csg,vaidyanathanms/votca.csg,Pallavi-Banerjee21/votca.csg,vaidyanathanms/votca.csg,Pallavi-Banerjee21/votca.csg,vaidyanathanms/votca.csg,Pallavi-Banerjee21/votca.csg,vaidyanathanms/votca.csg,Pallavi-Banerjee21/votca.csg,Pallavi-Banerjee21/votca.csg,vaidyanathanms/votca.csg