support for mute and audio stream changing buttons

[tvidal-net]

I am not sure if you are still maintaining this, but I needed to add some functionality to support mute/unmute of the microphone or speaker, as well as to change the capture and playback streams altogether, so I implemented a couple new widget types called widget_mute and widget_audio respectively.

There's also a few other changes to rationalise some of the names as well as error and verbose logging. Let me know your feedback, I am happy to fix any change you request if you are willing to merge.

Thank you!