removes timezone info before storing in hdf5 to avoid append errors
removes timezone info before storing in hdf5 to avoid append errors

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