Use chef-runner on Windows (part 1)

Allow to use chef-runner under Windows.

* [x] Fix tests to run under mingw32 ("Git Bash")
* [x] Fix tests to run under cmd.exe
* [x] Cross-compile Windows binaries
* [x] Disable color output (done in #27)

TODO:

* rsync: use destination-default permissions (`--no-p --no-g --chmod=ugo=rwX`)
* Write docs