Added authorization operations

Added authorization operations and ability to get connection by authorization token.
I agree. Ok, I can make LIST_AUTHORIZATIONS apart of this PR then!

public Collection getAuthorizations();
public IAuthorization getAuthorization(String id);

Expired authorizations shouldn't be returned from the LIST_AUTHORIZATIONS operation. 
Also, "expires_in_seconds" looks beneficial to make apart of the authorization object too!!

http://openshift.github.io/documentation/rest_api/rest-api-1-6.html#authorization