add bitsy audio

add bitsy audio is a single player action game. It was developed by mark wonnacott and was released on December 3, 2018. It received mostly positive reviews from players.

recommend you use mp3 audio--support for different audio file types varies between browsers but mp3 seems to work almost everywhere for per-room audio, you can use David Mowatt's bitsymuse hack, which I have built an interface for here: https://kool.tools/bitsy/tools/bitsymuse-ui/