Implement #81 Sync Script.about with Github webhook

See: #81 

### Test
https://nameless-hollows-5487.herokuapp.com
Use `http://nameless-hollows-5487.herokuapp.com/github/hook` for your webhook.

### Summary

* Refactored the entire github hook, and parts of github import.
* Webhooks now return a status code on error, and return a `[err, jsFileList, mdFileList]` response on success. Eg:

 ```json
[null, [],
    [{
        "markdownBlob": {
            "path": "description.md",
            "mode": "100644",
            "type": "blob",
            "sha": "eff9a9a548a9017a45cb82a0f6562fddaf2e7aea",
            "size": 63,
            "url": "https://api.github.com/repos/ZrenTest/TestUserScript/git/blobs/eff9a9a548a9017a45cb82a0f6562fddaf2e7aea",
            "canUpload": true,
            "errors": []
        },
        "numScriptsAffected": 1
    }]
]
```

* Moved both controllers to their own files in a pattern I plan to expand to other controllers.
* Refactor `/model/settings.json` into `/config.js` which allows us to attach comments, parse env vars and provide defaults for them, and centralize all app variables.
* Rename `/user/*` routes to `/account/*`.
* Move express-minify to optionalDependencies. Do not minify when isDbg.

# Screenshots

![](http://i.imgur.com/J9wnbvL.png)
![](http://i.imgur.com/uA1UTy7.png)