add windows test/development compatibility

[skuschel]

The bash scripts run smoothly on a linux machine, but not under Windows. They have to be rewritten or windows pendants have to be added to make this work.

• [x] make run-tests work under windows. (Maybe include all tests in setup.py, so that ./setup.py test runs everything? having a single command will also make it very easy to set up a code coverage statistics #18 )
• [ ] setup a CI, which runs the test under windows.

[skuschel]

tests are windows compatible since 33891804