Fix compatibility with Windows

[8ctopus]

Solves all Windows related issues I could find (#1), without breaking functionality in linux based systems.
Works in both classic cmd.exe and mintty.

[talhasch]

@8ctopus thanks for contribution!

[talhasch]

@8ctopus it doesn't work with macos. error message i get:

Could not decode json: Syntax error
curl result: 0 {"time_namelookup": 0,030375,"time_connect": 0,047081,"time_appconnect": 0,131314,"time_pretransfer": 0,131455,"time_redirect": 0,000000,"time_starttransfer": 0,225138,"time_total": 0,228472,"speed_download": 55324,000,"speed_upload": 0,000}

Somehow curl returns wrong/incompatible json format.

[8ctopus]

@talhasch Sorry about that, I don't have a mac to test on but I did successfully test in Alpine linux. I'll send an updated pull request that should work on Mac later today.