fixed bad access on nil properties during set
fixed bad access on nil properties during set

kostiakoval/SwiftAddressBook,kostiakoval/SwiftAddressBook,dfinzer/SwiftAddressBook,jeffreybergier/SwiftAddressBook,jeffreybergier/SwiftAddressBook,samsungaccelerator/SwiftAddressBook,SocialbitGmbH/SwiftAddressBook,dfinzer/SwiftAddressBook,cwoloszynski/SwiftAddressBook,cwoloszynski/SwiftAddressBook,samsungaccelerator/SwiftAddressBook,jeffreybergier/SwiftAddressBook,SocialbitGmbH/SwiftAddressBook