Attempt at making a non-generic refactor-friendly BindableProperty. (Some back-story on the deprecation and my motivation: https://twitter.com/PatridgeDev/status/690620310870106112.)

SuperAwesomeButton.cs

public class SomeButton : Button {
    public string ExampleThing {
      get { return (string)GetValue(ExampleThingBindableProperty); }
      set { SetValue(ExampleThingBindableProperty, value); }
    }

    public static readonly BindableProperty ExampleThingBindableProperty =
      BindableProperty.Create(nameof(ExampleThing), typeof(string), typeof(Button), default(string));
}