Button Read Optimizations

[MicroBahner]

@alto777

The code in #30 will ignore button pressed shorter than shortPressMin. I would prefer to get a short press message no matter how short the button press, but that is a matter of opinion.

I think shortPressMin is in fact the debouncing time. This is his method of debouncing. Other methods of debouncing also do not recognise operations shorter than the debounce time.