* Add a flag to document all exported bindings
This adds a boolean flag called `document-exported` (defaults to false)
that effectively adds an empty comment to all exported bindings that do
not already have a JSDoc comment. It also does the same for the
members of exported classes and objects.
```js
export class C {
method() {}
}
```
Both `C` and `C#method` are now part of the generated documentation.
Related to #424
* Fix lint error
* Rebase and use options pragma in test file
* Create extractor type as a generalized comment/export getter
* Document exported extractor
