Fix for MSVC?

[mristin]

Thank you very much for such a nice library!

I had to integrate it in a project running on Windows. A couple of places had to be fixed since MSVC complained -- nothing big, mostly comparisons between a signed and unsigned value. Would you like me to create a pull request?

I also saw that suffix increments are written instead of commonly-used prefix increments (i++ instead of ++i). Would you like me to fix that as well?