Restore oAuth defaults after usage

If you use let's say foursquare (based on your demo), you set some defaults to Popup a window. So far so good. Then you want to login via Google. The defaults will get updated to google, but since google doesn't define a name, foursquare is going to be used, meh, not a problem. Then you try foursquare again and then, it sets some `requiredUrlParams` , `optionalUrlParams`... (You can see them on the popup url). 

I don't think foursquare is gonna care about that, but imagine (I am null at `oauth` so maybe this example never comes to true):

* I don't want to send `scope` to Google, so I remove it.
* I logout, then I try Facebook which puts that `scope`.
* I logout, then I try Google again, and the `scope` will be there so that will be bad (supposing that does something bad)

Anyhow, we really need to restore our defaults after usage, there is no reason to not to.