nyc examples

I've recently had great success with https://github.com/bcoe/nyc and wanted to know if you could add an example using that for coverage. If it helps I can probably provide the example myself, though may need a few weeks.

You literally just need to run something like this:

```
nyc --require babel-register --require babel-polyfill mocha
```

It doesn't need `_mocha` or anything like that. Works great!

Inspect the repository's existing testing examples and documentation to find where a coverage example belongs. Add an example using nyc with babel-register, babel-polyfill, and mocha, and confirm that the documented command works without _mocha.

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