Parsing with `stoul` is not portable

[janhohenheim]

std::size_t is not guaranteed to be an unsigned long. Code like this will fail on some architectures.

Possible fix

[janhohenheim]

This breaks sane windows builds and is unsafe. Possible solutions:

• use sscanf_s on windows instead with some precompiler hacking
• #define _CRT_SECURE_NO_WARNINGS and #undef it again if it wasn't defined before
• switch to another method

[jeremystucki]

Closed with #64