[HentaiFoundry] Support downloading stories

[chrsmlls333]

I would to suggest the HentaiFoundry extractor be expanded to support stories:
Here is a blank example (not mine): http://www.hentai-foundry.com/stories/user/hiro08/35237/test
The URL pattern is: http://www.hentai-foundry.com/stories/user/____

There is a pdf which could be downloaded quite easily (I would think) or parse the actual story text. I'm not familiar with Python otherwise I would make a pull request. Thanks, the extractor works great other than this. gallery-dl has replaced many little sub-par programs in my arsenal so far!

[chrsmlls333]

Please label this feature-request and nsfw