Add notebetter:volume_control

[SoniEx2]

Putting a noteblock below a noteblock should enable volume control. Volume control should be done by using the noteblock below as the volume and the noteblock above as the pitch, and the block below the bottom noteblock as the instrument.

The idea with the NoteBetter API and the NoteBetter events was to allow for things like this: combo instruments.

You put a noteblock at the top. Then you put modifiers all the way down. Then you put an instrument.

I personally thought it was a quite beautiful way to do it.

[SoniEx2]

Here's how notebetter:vanilla_fallback works, as an example: https://github.com/ShinkoNet/NoteBetter-2/blob/master/src/main/scala/com/github/soniex2/notebetter/VanillaFallbackSoundEvent.java

[ShinkoNet]

So by editing the value/pitch in the note block that's below the top note block, the volume can change? It sounds like a great idea.

[ShinkoNet]

Used this idea for a "control" instrument in NBS2CBS, which allows stereo panning, volume, sustain and pitch alterations depending on the pitch of the instrument and how many there are of it.