Windows merge (master & dev_tools)

The ha-feature-windows branch is pretty outdated. I want to start sending some PRs to it, but the first one will be pretty hard to review if the branch isn't rebased first. This PR merges master & https://github.com/travis-ci/travis-cookbooks/pull/300 (the Vagrantfile setup) into ha-feature-windows.

I took care of the merge conflicts between https://github.com/travis-ci/travis-cookbooks/pull/300 and https://github.com/travis-ci/travis-cookbooks/pull/289 ("dev tools", i.e. test-kitchen setup).