Stack and streaming conformer support (#141)

* added csrc/stack.cc

* stack: added checks

* added copyright info

* passed cpp style checks

* formatted code

* added some support for streaming conformer model support (not verified)

* code lint

* made more progress with streaming conformer support (not working yet)

* passed style check

* changes as suggested by @csukuangfj

* added some debug info

* fixed style check

* Use Cat to replace Stack

* remove debug statements

---------

Co-authored-by: Jingzhao Ou (jou2019) <jou2019@cisco.com>
Co-authored-by: Fangjun Kuang <csukuangfj@gmail.com>

sherpa-onnx/csrc/online-zipformer-transducer-model.cc

@@ -434,7 +434,8 @@ std::vector<Ort::Value> OnlineZipformerTransducerModel::GetEncoderInitStates() {
 
 std::pair<Ort::Value, std::vector<Ort::Value>>
 OnlineZipformerTransducerModel::RunEncoder(Ort::Value features,
-                                           std::vector<Ort::Value> states) {
+                                           std::vector<Ort::Value> states,
+                                           Ort::Value /* processed_frames */) {
   std::vector<Ort::Value> encoder_inputs;
   encoder_inputs.reserve(1 + states.size());