Ask user to allow access to his address book

This code refers to ONLY asking for the address book permission and not doing any related manipulation. The code has been tested for iOS 7.

Note: If ABAddressBookGetAuthorizationStatus() returns a value other than kABAuthorizationStatusNotDetermined, NO access alert is shown.

Possible values from ABAddressBookGetAuthorizationStatus() is given by:

Reference:

• ABAddressBook Reference
• ABAuthorizationStatus Constants