Returns a tuple of names and zero arrays for LSTM init states

def lstm_init_states(batch_size):
    """ Returns a tuple of names and zero arrays for LSTM init states"""
    hp = Hyperparams()
    init_shapes = lstm.init_states(batch_size=batch_size, num_lstm_layer=hp.num_lstm_layer, num_hidden=hp.num_hidden)
    init_names = [s[0] for s in init_shapes]
    init_arrays = [mx.nd.zeros(x[1]) for x in init_shapes]
    return init_names, init_arrays