running example: source_code/is_score 1v7bABAB_int.pdb 1v7bABAB_con.lst 2b3nAB.parsed 2b3nABAB_con.lst 1v7b-2b3n.ialign.txt source_code/is_score 117eABAB_int.pdb 117eABAB_con.lst Complex_6650gAB_int.pdb Complex_6650gAB_con.lst isscore_result