implement vanilla RNN and LSTM and a corresponding example. This [one](https://pytorch.org/tutorials/intermediate/char_rnn_generation_tutorial.html) may be a good starting point. - [x] RNN - [ ] RNN unit tests - [x] RNN example - [ ] LSTM - [ ] LSTM unit tests - [ ] LSTM example - [ ] GRU - [ ] GRU unit tests - [ ] GRU example
