Update AFOAuth1Client to use ARC and latest AFNetworking

I've updated AFOAuth1Client to use ARC and use the latest version of AFNetworking (via a submodule).

Both the iOS and OSX example apps have also been updated.

There are two issues:

1. I had to copy `AFPercentEscapedQueryStringPairMemberFromStringWithEncoding` from AFHTTPClient.m into AFOAuth1Client.m as you cannot access it any other way.
2. The `UIApplicationDidFinishLaunchingNotification` notification does not get called when relaunching the app from the background (which always happens when we authenticate with OAuth). I'm not sure how else we can get the URL.

Let me know your thoughts.