Fix RPSL explorer compilation not working on Windows

[Mcgode]

The RPSL compilation command does not work on Windows, and seems to have been designed for Unix-like systems.

This PR fixes the command line for Windows, while keeping compatibility with Unix systems.
Addresses #28

[expenses]

I think using the std::filesystem:path functions would be tidier: https://en.cppreference.com/w/cpp/filesystem/path/make_preferred. But I'm not sure what version of c++ RPS is targetting.

[Mcgode]

Indeed, thanks for the comment.

The RPS lib itself target C++11 but rpsl_explorer.hpp itself uses C++17 (and already uses std::filesystem::path in the same function)