* If the `:{en|dis}able` command would have no effect, change all other
shells to the inverse enable value
* Consistently add a space between the shell name and the colon to ease
parsing the output
* Provide exit code aggregated from all remote shells by taking
the maximum
* Rename `:export_rank` to `:export_vars` as it now also exports
the hostname
* Add `--password-file` to login using a password
* Support `.zip` files on file transfer
* Switch from `setuptools` to `distutils`
* Color hostnames in the output