/*    
        Ref: http://developer.github.com/v3/oauth/
        Ref: https://github.com/settings/applications/new
        Ref: http://developer.github.com/v3/markdown/

        POST to: https://github.com/markdown { text: 'text', mode: 'markdown' }
        Response: body

        if error:
            1. redirect to: https://github.com/login/oauth/authorize
                ?client_id=APPID
                &redirect_uri=http://HOST:PORT
                &state=RANDOM
            
            2. catch the ?code= param
    
            3. server POST to: https://github.com/login/oauth/access_token
                ?client_id=APPID
                &client_secret=APPSECRET
                &code=CODE
                &state=RANDOM
            
                header: Accept: application/json
                response: { access_token: }
        
            4. repeat the POST as /markdown?access_token=ACCESSTOKEN
        
            5. if error, go again with the redir, user will bail out as they see fit
    */