Version 3.1 adds an adjustable settle time for interrupts which allows for the debouncing of noisy inputs. You can change this when you register a pin number on the PortEventListener like so:

listener = PortEventListener(port)
listener.register(pin_num, direction, callback, settle_time)

settle_time is optional and defaults to 0.020 seconds.

The packages for this release have been temporarily removed because they do not install correctly. A new release will be released very soon (sometime today 17/09/2013).