fixes target installDir does not exist bug;  adds a 'clean' option
fixes target installDir does not exist bug;  adds a 'clean' option

itesla/ipst,itesla/ipst,itesla/ipst-entsoe,itesla/ipst-entsoe,itesla/ipst-core,itesla/ipst,powsybl/powsybl-core,itesla/ipst-core,itesla/ipst-core,itesla/ipst,powsybl/powsybl-core,itesla/ipst-core,itesla/ipst,itesla/ipst,itesla/ipst,itesla/ipst,powsybl/powsybl-core