[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.
I'm uneasy about the resources this will leave allocated.  It seems reasonable to leave the acceptance nodes running if an explicit `--keep` flag is given.  I'm not so sure about leaving them running just because the tests fail.  I think the user should have to ask for this behavior because if they get it, they become responsible for the cleanup themselves.