###Note Apple will reject apps that are using private url schemes (Ugh, Apple....) if they are pretty much obvius. Some apps are rejected and others are not, so, be aware of this issue before implementing any of those URL's in your app as a feature.
###[UPDATE : Not yet tested in iOS 10. It will fail because of policies changes in URL scheme handling.]
###[UPDATE 2:The openURL() method of UIApplication is now deprecated. You should use application(_:open:options:) instead]
Sometimes we need to open Setting's Preferences not of our app, but of the iPhone itself. What should we do to acomplish this?