TypeError: 'Tensor' object is not iterable.

Thanks for your great work! I wonder have you tried using LSTM to run the model? Seems this error will occur when I set `use_lstm=True`: `TypeError: 'Tensor' object is not iterable.`. And it points to [this line of code](https://github.com/Chung-I/Variational-Recurrent-Autoencoder-Tensorflow/blob/master/seq2seq.py#L166). Do you have any idea about it? Thanks in advance!