add another vagrant role that also includes baragon + nginx

This adds an additional Vagrant role (is that the right term?) that runs Baragon and nginx in addition to Mesos and Singularity. This is useful for testing out web services in Singularity.

To use:
```
vagrant up test-baragon
```

Example request:
```json
{
  "id": "test",
  "daemon": true,
  "instances": 3,
  "rackSensitive": false,
  "loadBalanced": true
}
```

Example deploy:
```json
{
  "deploy": {
    "requestId":"test",
    "id":"1",
    "resources" {
      "cpus":0.1,
      "memoryMb":128,
      "numPorts":1
    },
    "serviceBasePath":"/",
    "healthcheckUri":"/",
    "skipHealthchecksOnDeploy":false,
    "loadBalancerGroups":["vagrant"],
    "command":"python -m SimpleHTTPServer $PORT"
  }
}
```

Should be accessible via http://vagrant-singularity/.

@eliast you should be able to take advantage of this for your re:invent demo

/cc @wsorenson @gchomatas