Introducing github actions (based on travis.yml)

[raven-wing]

[raven-wing]

I'd be glad to create whole CI process here, but current build system has flaws (e.g. some tests are not passing, yet build is - test scripts are having bugs - they should be replaced).

This PR is building python wheels (which allows you to pip install ) and basically - runs test, so it's better, then current solution (which has no CI at all), yet - to make it right (maybe in future PR) I would need some assistance. Someone who actually could make all tests pass would be appreciated.