Add rotary speed as a parameter to the new dual foot switch feature in 4.1.0

Add rotary speed to new dual foot switch feature.

Better yet, open up all parameters in all blocks for the dual [Stomp] footswitch feature.

It seems like the limited number of blocks that can accept this feature in 4.1.0 were chosen as a test case; hopefully all block types will have this available in the future.

This was my first thought as soon as I read about the dual stomp and was very disappointed to see that it did not apply to the speed control on the rotary effect. It is a pain to jump between the speeds and there’s no ramp up/down. Would be even better if a single footswitch could activate the effect and then hold it down to change speeds.