Added metadata to export_csv; 2 places of decimal
Added metadata to export_csv; 2 places of decimal

HarllanAndrye/nilmtk,jaduimstra/nilmtk,pauldeng/nilmtk,AlexRobson/nilmtk,nilmtk/nilmtk,josemao/nilmtk,nilmtk/nilmtk,mmottahedi/nilmtk