TSD is deprecated, replace with Typings

On `npm install` of a fresh clone, I get

```
npm WARN deprecated tsd@0.6.5: TSD is deprecated in favor of Typings (https://github.com/typings/typings) - see https://github.com/DefinitelyTyped/tsd/issues/269 for more information
```

For clicking convenience, the above issue is [here](https://github.com/DefinitelyTyped/tsd/issues/269).
