A little of coordination for Rosettacode

[bearophile]

> With functions like this my last version will become simpler, 
> and it's equally statically type safe:
>
> bool xor(in bool[2] args) pure nothrow {
>     return b[0] != b[1];
> }

This third version is much simpler and it seems good enough for
Rosettacode:

http://codepad.org/YJjb1t91

Bye,
bearophile