Add button parsing from MIDI data

[pixsperdavid]

The external should be able to take an input MIDI stream, and using the Push 2 button mappings, output button status using human-readable symbols.

[philipkobernik]

Hey David, I used imp.push to create a digital instrument for push 2 that sends graphic feedback to the screen -- imp.push makes the push2 a unique dev target for max/msp/jitter instruments

So thanks!

I come from js/ruby development, haven't worked in c, but would love to contribute to your roadmap for imp.push if I can.

I can imagine that imp.push would take [midiin] data via an inlet, then do some internal state management to turn LED lights on when the button is pressed, etc.

I'll brainstorm on how this external might interact with state to handle features like "setting default push button/knob state on load" ...

Cheers, Philip