replaced the oauth additions file with the more standard file naming convention for objective C categories
oauthcore is now an objective C class rather than pure C functions. This will allow me to use function overloading. Function overloading is important because different OAuth calls ask for different parameters. For instance oauth_callback and oauth_verifier are sent in one type of request
fixed copyright notice
converted project to ARC
added readme
added a method for sending the oauth verifier