Introduce semantics-release

[markusguenther]

It would be so nice to have semantic-release. In combination with commitizen that would automate the release process and enables members of the project to release also in npm.

Only thing we need is a valid npm_token and need to create a travis project. Could also help with that.

https://github.com/semantic-release/semantic-release

https://github.com/commitizen/cz-cli