Javascript bindings (#14)

* Initial version ready

- bindings are in `bindings/emscripten.cpp`
- minimal Javascript example is in `examples/ggwave-js`

* add npm package + add test-ggwave.js

* js : rename export name to "ggwave_factory"

* update to v0.1.5

* Update README.md

* npm : add npm-publish target

examples/ggwave-to-file/main.cpp

@@ -67,7 +67,6 @@ int main(int argc, char** argv) {
         return -3;
     }
 
-
     fprintf(stderr, "Generating waveform for message '%s' ...\n", message.c_str());
 
     GGWave ggWave({ GGWave::kBaseSampleRate, sampleRateOut, 1024, GGWAVE_SAMPLE_FORMAT_F32, GGWAVE_SAMPLE_FORMAT_I16 });