decoder for open vocabulary keyword spotting (#505)

* various fixes to ContextGraph to support open vocabulary keywords decoder

* Add keyword spotter runtime

* Add binary

* First version works

* Minor fixes

* update text2token

* default values

* Add jni for kws

* add kws android project

* Minor fixes

* Remove unused interface

* Minor fixes

* Add workflow

* handle extra info in texts

* Minor fixes

* Add more comments

* Fix ci

* fix cpp style

* Add input box in android demo so that users can specify their keywords

* Fix cpp style

* Fix comments

* Minor fixes

* Minor fixes

* minor fixes

* Minor fixes

* Minor fixes

* Add CI

* Fix code style

* cpplint

* Fix comments

* Fix error

sherpa-onnx/csrc/hypothesis.h

@@ -28,6 +28,10 @@ struct Hypothesis {
   // on which ys[i] is decoded.
   std::vector<int32_t> timestamps;
 
+  // The acoustic probability for each token in ys.
+  // Only used for keyword spotting task.
+  std::vector<float> ys_probs;
+
   // The total score of ys in log space.
   // It contains only acoustic scores
   double log_prob = 0;