Upgrades to seamlessly work with the latest Silverstripe release.

These changes use the latest 'add_extension' syntax and allow validation to work over the Member object by default.

Problems were:
- Code could not run as add_extension's was not using the current parameters.
- Unable to validate the member object (and thus cannot add groups, permissions, etc) due to the email field being missing (depending on the parameters that your facebook application uses).