Fixed support for skip_info option to ensure raw_info isn't called

Currently, the skip_info option isn't working as expected. When skip_info is enabled, there should be no follow-on API call to Twitter to fetch the user's information. However, raw_info is being populated in auth_hash.extra regardless of the skip_info option. This patch fixes auth_hash.extra to only include raw_info when skip_info is false.
Use the new Ruby 1.9 hash syntax.