extend curLabel range to [0..std::limits<unsigned long long>::max()] …

[avilleret]

…and warp when reaching limits

fix ##193

I made a code snippet to try to trig the issue, but std::numeric_limits<usigned long long>::max() is to hard to reach...

here is the code : https://gist.github.com/avilleret/ad41050756401d1ef0bef78ec1995ced

[kylemcdonald]

i see what you're suggesting here, but without taking a closer look i'm not sure your solution is correctly implemented.

for example, you shouldn't need to use a modulo operator to wrap something at its boundaries:

unsigned byte a = 255;
unsigned byte b = a + 1; // b == 0

i think if you remove that line then i can merge this PR.

[avilleret]

you're absolutely right, it was my mistake