create ability to view sample dataset from facebook

**This is not intended to be merged**, but see what can be learned from my first attempt to include another dataset.

To view, run this from the root of the repo
```bash
git fetch
git checkout -b facebook-sample origin/facebook-sample
./scripts/get-facebook.sh
```

Then start the server locally as you normally would.
```bash
source env/bin/activate
foreman start
```

Nodes are labeled as numbers.

### Let me know what you think.

[source website](http://snap.stanford.edu/data/)