Expander for Quad Operator's Algorithm Functionality

Where the Quad Operator on its own maintains a one knob per function design discipline, we nevertheless recognized the value of some more advanced algorithm-oriented functionality.

The Algo expander for the Quad Operator provides:
- Saving and loading of modulation send knob positions for FM algorithm design reuse
- Crossfade between pairs of saved algorithms, or a saved algorithm and the live knob positions