bypass: use library function

[magnetophon]

This causes the GR meters to return to zero when bypassed; which can be considered both a feature and a bug, depending on your POV.

Personally, I find it confusing when the GR meter of a bypassed processor is moving.

[trummerschlunk]

There we have different points of view ;) For that reason I wrote the custom bypass.

[trummerschlunk]

This is how most analog mastering consoles do it, so the inserts are fed with audio during bypass comparison.