[FLOC-1070] Acceptance test runner.

The tutorial Vagrantfile hard-codes the version of the tutorial base box, which means that it needs to be edited to run tests against other versions.

This provides a new Vagrantfile, and a test runner that invokes it. Hopefully, the new runner should also be able to deal with cloud VMs eventually too.
Try downloading the file, and then passing the path to it. The problem with it, is that it isn't being served as JSON, currently. This is fixed [here](https://github.com/ClusterHQ/build.clusterhq.com/pull/43/files#diff-6f1da70fdc6f113023ada604f7fd64c5R157), but that isn't currently deployed :/. You could test that http works, by putting that file somewhere, and
```
twistd web --path /parent/path/of/json -m application/json
```
and doing ``vagrant box add http://localhost:8080/flocker-tutorial.json`` (approximately).

The failure of the upload is simply because I didn't provision credentials on the staging builder. (The upload didn't need testing)