* Add emformer model.
* Copy files.
* Use Emformer model as RNN-T encoder.
* Support streaming decoding.
* Minor fixes.
* Add RNN-T Emformer for Aishell.
* Add modified beam search for pruned rnn-t.
* Fix style issues.
* Update RESULTS.md.
* Fix typos.
* Minor fixes.
* Test the pre-trained model using GitHub actions.
* Let the user install optimized_transducer on her own.
* Fix errors in GitHub CI.