Added an ability to inspect state machine chains

[YohDeadfall]

That pull request improves debugging experience, so a dev using Kinetic can easily check what state machine a chain of LINQ calls produced:

var source = new PublishSubject<int>();
var observer = source   // + observable
                        // ├ ObserverStateMachine
    .Where(x => x > 0)  // ├ WhereStateMachind
    .Select(x => x + 1) // ├ SelectStateMachineelectStateMachine
    .ToObservable();    // └ ObservableStateMachine