added class function to create additional instances of SwiftAddressBook (solves #59)
added class function to create additional instances of SwiftAddressBook (solves #59)

dfinzer/SwiftAddressBook,samsungaccelerator/SwiftAddressBook,SocialbitGmbH/SwiftAddressBook,samsungaccelerator/SwiftAddressBook,dfinzer/SwiftAddressBook,SocialbitGmbH/SwiftAddressBook