#define probable name collision in CAT9555.h

[AlexanderBrevig]

https://github.com/arduino-org/arduino-library-lucky-shield/blob/master/src/lib/CAT9555.h#L47

We should discourage the use of #defines as the compiler will do an excellent job of optimizing constants too and then they're scoped correctly :)

If the pins are tightly (wired) bound to a function then maybe the whole gpio() thing is a fallacy and we should expose a method per pin function?