API now supporting audio file selection
You can now select a list of available extensions to load instead of the default mp3 files.
OGG audio files seems a good idea because of a free license and a lighter file size (be aware that not all browsers support ogg format, so you still need to add your mp3 files just in case).
Avoid BGM to stop

Finally support BGMFileExtension API.
Avoid BGM to restart if playing it again.
Fix some audio problems.
- Fix typo error.
- Allow server config to overwrite BGMFileExtension config.
- Only rewrite audio extension for remote files only.
- Stop sounds when moving back from game to character selection.
Merge pull request #64 from vthibault/audio-format-support

Add support for ```BGMFileExtension```