Fix Vosklet browser cache handling and recognizer event bridge

- fix broken cached model loading
- cache validated TAR models instead of gzip responses
- add proper fireEv bridge for wasm/js events
- fix recognizer initialization callbacks
- fix Embind waveform return type handling
- stabilize acceptWaveform in minified builds
- add optional debug logging

src/Recognizer.h

@@ -11,7 +11,7 @@ struct Recognizer
   Recognizer(int index, float sampleRate, CommonModel *model);
   Recognizer(int index, float sampleRate, CommonModel *model, CommonModel *spkModel);
   Recognizer(int index, float sampleRate, CommonModel *model, const std::string &grm, int);
-  const char *acceptWaveform(int start, int len);
+  std::string acceptWaveform(int start, int len);
   void reset();
   void setEndpointerMode(VoskEndpointerMode mode);
   void setEndpointerDelays(float tStartMax, float tEnd, float tMax);