support requiring json files

I think json support is quite natural, partly because it is supported in npm, but also because in practice, it is a core part of javascript.

My use case:

In my component.json for my tests i have
```json
{
 "scripts": [
    "index.js",
    "test-this.js",
    "test-that.js",
    "test-alot-more-like-this.js",
    "component.json"
  ]
}
```

and I'd like to be able to do this in `index.js`
```javascript
require('./component').scripts.forEach(function (script) {
  require('./' + script);
})
```