user_osc_param does not expose velocity data

[jakebromberg]

Is your feature request related to a problem? Please describe.
I would like to modulate my oscillators based on velocity input. Currently this is unavailable via the user_osc_param, which would seem like a likely place to pull this from.

Describe the solution you'd like
I do see that the user_osc_param has an extra three bytes of padding. Allocating one of those bytes for velocity measurements seems like a reasonable solution.

[etienne-korg]

Velocity is currently not available in the oscillator runtime, but request noted.

[ptarabbia]

Yes please ! That would be extremely useful

[seanwayland]

This would be so useful. All my years of piano practice and keyboard practice could be put to good use !