I downloaded your code from GitHub and used your example above. Works like a charm on my Arduino Mega 2560 r3. I played with the interval and even at one 1ms (vs the default 4ms) it works like a charm touching two wires together. One interesting observation is when one sets the interval to say 120 (about 1 second for the eight pins checked) is that it takes a second (obviously), before it issues the status when pulling down an pin (touching the pin wire to gnd, but is essentially instantaneous when you disconnect.
Thank you again.