Sed command does not work with windows

[fanbyprinciple]

I think it is important to mention in readme that this python module is only for linux systems.

[eltrevii]

@fanbyprinciple you can edit the main file and make a pull request

[fanbyprinciple]

Will look into it thanks! @Aritz331

[superswan]

I've replaced the sed commands with pure python. Enjoy. #8