gams_dir can be explicitly defined

[kavvkon]

I had trouble running the library without defining explicitly the gams directory as my GAMS installaiton couldn't be located by 'which'.

Moreover I added gdxcc as a requirement in setup.py so that it can be automatically installed by pypi (maintained by me here )

[khaeru]

Great to see that someone's figured out how to package gdxcc! Honestly, the most laborious part of maintaining this package has been helping my colleagues do that first step of installing the low-level bindings. That should help a lot.

Happy to merge this shortly, but one question first—are you using Windows? I previously noted there was a program where available, so I was thinking to expand api._gams_dir() to (1) check sys.platform and (2) try where gams.exe to identify the gams_dir.

If you want to take a stab at that, it would be (even more) appreciated. But if you're not on Windows, that's fine—I'll just merge it directly.

[kavvkon]

Hey, glad you liked it. I will propose something as we have this kind of checks in another piece of code.

I have both windows and linux and shutil works in the same way I think..