Implemented debouncing of interrupts (Github Issue 5)

[fcrossen]

Implemented as per the suggestion in that thread.
Updated README.md.
Unit tests need additional coverage to cover debounce and migrating to cover later versions of PHPUnit.

[AndrewCarterUK]

Thanks very much for this feature, it looks well done and very useful - I have briefly read through it and the only comment I would make is that adding a parameter to a function on a public interface is a relatively significant backwards incompatible change.

It would probably be less of an issue to maybe add getDebounceTime() and setDebounceTime() to InputPinInterface, as it's unlikely anyone has extended/implemented these.

On a related note: I'm looking for someone to maintain this repository and if I can't find someone I'll probably mark the repository as inactive and then provide instructions for users on how to run this feature branch in the README.

[svpernova09]

It would probably be less of an issue to maybe add getDebounceTime() and setDebounceTime() to InputPinInterface, as it's unlikely anyone has extended/implemented these.

[fcrossen]

Morning guys,
I'll make the changes when I get a chance - but not for another couple of weeks I'm afraid. Thanks for the suggestion.
I'm not sure how I can help in maintaining - my experience with GPIO is limited to say the least, and I used this for a very specific use case that might never be revisited. But I'll certainly have a think about how I (or a colleague) could help.