Added addresses and Record IDs to APContact

I had a need for access to contact addresses, and address book record ids (for re-accessing at a later date), so I added those properties and field mask options. So far everything seems quite sane and stable, and the changes are quite minimal, so I thought I'd push it upstream.

The only thing of note about this is that `APContact`'s addresses property is an `NSArray` of `NSDictionaries`, accessed using the `kABPersonAddress<blank>Key` constants from the `AddressBook` framework. Since that's different from the rest of `APContact`, it should probably be documented somewhere.

Thanks for the great library, it's quite useful and was _very_ easy to extend.