OAuth 1.0 fix: callback parameter is added to the /oauth/authorize request 

I tried to use the latest grails oauth plugin, and came across the issue that the callback parameter is not added to the /oauth/authorize request so that the remote website(dropbox, for example) cannot redirect to the app. I took a look at the scribe API source code as well, and I believe that the root cause for this issue is on the scribe side. With this in mind, I think the solution proposed on the plugin side is a temporary fix. 

Please take a look at the code change. Thanks.