Support MvvmCross-Bindings to IObservable<T>-properties in view models.

By overriding the initialization process in MvvmCross to use ObservableSourceBindingFactory, view models may expose properties of Type IObservable<T>. The changes in the Observable will then be observed by the binding and be reflected by the UI.

Note:

• This does only work for properties of type IObservable<T> where T is a reference type. If you need this for value types, project your observable to IObservable<object> by boxing the values.
• The view model must ensure that the changes on the observable are observed on the UI-Thread. You may use the ObserveOn(IMvxMainThreadDispatcher) extension method for this.