Translate context when importing common JS modules.

I have not done enough research on this problem to explain why so I will just start with an example.

``` js
import D3 from 'd3';

console.log(D3);
```

This code throws the error because the document object cannot be found on the this context. 

This translator might need to set the global context of the import as the window as opposed to leaving it undefined per es6 modules.
