Multi-function "sticky" knob states + instant feedback

[wraybowling]

Use some sort of LED flashing of the ALT light as well as perhaps a visualization on the orange grid about the value. Also don't write any value unless the knob was turned. Similarly, the original function should not change once Alt is released unless the knob is turned again. There's some quickly written code in develop right now to do this for clock divide input, but formalize it as a function or class to save memory.

• create new class for detecting if knob changed
• replace current prev/next variables with new objects