A simple mortgage calculator for mortgage amortization schedule and the ROI from the rental income. This is the Swift project in the Apress Books, Migrating to Swift programming (ISBN-13: 978-1484204375 and ISBN-13: 978-1484209325). It demonstrates the following common programming topics in Swift: * Consume remote RESTFul service. * Save data. * Common UIKit User Interface including screen navigations and animations.