add Windows testing

[mschilli87]

see #36 & #42

[mschilli87]

@retaj: Why the merge? The tests are still failing aren't they?
Now I cannot re-base on dev anymore until it's fixed upstream.
Also, the badge was still missing.
That's why Iabled this WIP and assigned myself. 😉

[retaj]

I have no idea what happened here 🐙 😱 🙀

[mschilli87]

I created a new dev2 branch which is basically dev without this merge.
I re-created this PR as #44 targeting the new branch and I updated #40 & #42 to target the new branch.
So theoretically (if you agree), we can delete the dev branch and use dev2 from now on (until the next merge to master).

[mschilli87]

@retaj: I rebased dev and re-targeted all PRs. So when all tests are through I'll remove dev2 again. Sorry for the force-push to dev but it seemed like the cleanest solution to me.
Let me know if this breaks anything locally for you and I'll help you re-base/merge everything into dev again. 😉