Feature request: muted property

[gonzaloarca]

It'd be useful if the library had a muted property like the HTML5 Audio Element does, since setting the volume to 0 doesn't accommodate to this feature in its entirety. Being able to mute implies having the volume property untouched, but still having no sound coming out. This is especially reflected in most player UIs, where the user is able to toggle and untoggle the mute button, and the volume is still preserved when unmuted.

Judging from the style of the library, this would probably mean having getMuted and setMuted methods defined in the Gapless5 object