or higher.
- Use `--machine-readable` output for `status`, `box_list`, and `plugin_list`.
- Allow arbitrary status codes, so new statuses do not break parsing.
Previously, statuses were constrained to known ones for the sake of parsing.
Now that machine-readable vagrant output is being used, any status can be
parsed.
- Status value constants (e.g. vagrant.Vagrant.NOT_CREATED) have changed to
match the "state" value returned by the `--machine-readable` output of
the `vagrant status` command.
- The box version is now returned for a box listing