Added setVolume(), setTempo(), mute() and loop mode features

[fredzo]

Hi Fabiano,

I'm working on a Tetris game for Awtrix/Ulanzi desktop clock (https://github.com/fredzo/awtris) and I've been in need of some new features in your great melody-player library !
Here is a PR with this new features :

• new playAsync() parameters to allow loop mode on current melody and callback function to be called at the end of the melody
• new setVolume() method to change piezo duty-cycle on ESP32 platform to adapt music volume
• new setTempo() method to change the tempo of current melody
• new mute() method that allows muting the melody while playing a sound effect, for example, with another player (on the same pin) and go back to the melody afterwards

Please let me know if you have any comment or need any change.

Best regards,

Frederic.

[fabianoriccardi]

Great work! I have given a look to the code, and it is well integrated in the rest of the library. Note that the CI tests doesn't pass on ESP32 v1.0.6 (there is a re-order issue). However, before merging, I would test it on hardware.

[fredzo]

OK great, thank you for you feedback !
Let me know if I can help, I'm not familiar with the re-order issue you mentioned on ESP32 v1.0.6...
I've tested all the modifications on an Ulanzi Desktop Clock (ESP32) in async mode.

[fabianoriccardi]

Ok that's fine, I will fix it.